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HARVARD UNIVERSITY

LIBRARY

OF THE

Museum of Comparative Zoology

UNIVERSITY OF KANSAS

SCIENCE BULLETIN

MUS. CO?v?P. ZCOL

JAN -4.1961 IIMlyEHSlTY

UNIVERSITY OF KANSAS PUBLICATIONS University of Kansas Science Bulletin - Vol. XLI

December 23, 1960 Lawrence, Kansas

ANNOUNCEMENT

The University of Kansas Science Bulletin (continuation of the Kansas University Quarterly) is issued in parts at irregular inter- vals. Each volume contains from 500 to 1,800 pages of reading matter, with necessary illustrations. Exchanges with other institu- tions and learned societies everywhere are sohcited. All exchanges should be addressed to

The University of Kansas Science Bulletin, Library of tebe Universfty of Kansas, Lawrence, Kan.

PUBLICATION DATES

The actual date of publication (i. e., mailing date) of many of the volumes of the University of Kansas Science Bulletin differs so markedly from the dates borne on the covers of the publication or on the covers of the separata that it seems wise to offer a corrected list showing the mailing date. The editor has been unable to verify mailing dates earHer than 1932. Separata were issued at the same time as the whole volume.

Vol. XX— October 1, 1932. XXI— November 27, 1934 XXII— November 15, 1935. XXIII— August 15, 1936. XXIV— February 16, 1938. XXV— July 10, 1939. XXVI— November 27, 1940. XXVII, Pt. I— Dec. 30, 1941. XXVIII, Pt. I— May 15, 1942. Pt. II— Nov. 12, 1942. XXIX, Pt. I—July 15, 1943. Pt. II— Oct. 15, 1943. XXX, Pt. I— June 12, 1944. Pt. II— June 15, 1945. XXXI, Pt. I— May 1, 1946. Pt. II— Nov. 1, 1947.

Vol. XXXII— Nov. 25, 1948.

XXXIII, Pt. I— April 20, 1949. Pt. II— March 20, 1950.

XXXIV, Pt. I— Oct. 1, 1951. Pt. II— Feb. 15, 1952.

XXXV, Pt. I— July 1, 1952. Pt. II— Sept. 10, 1953. Pt. Ill— Nov. 20, 1953. XXXVI, Pt. I— June 1, 1954. Pt. II— July 15, 1954. XXXVII, Pt. I— October 15, 1955.

Pt. II— June 29, 1956. XXXVIII, Pt. I— Dec. 20, 1956. Pt. II— March 2, 1958. XXXIX— November 18, 1958. XL— April 20, 1960.

Editor RuFus H, Thompson

Editorial Board.

R. H. Thompson, Chairman Charles Michener Paul Roofe David Paretsky worthie h, horr Parke H. Woodard, Secretary

UNIVERSITY OF KANSAS

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Volume XLI

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Contents of Volume XLI

No. PAGE

1. Keys to Subfamilies, Tribes, Cenera and Subgenera of

the Gerridae of the World,

Herbert B. Hungerford and Ryuichi Matsuda, 3

2. Morphology, Evolution and a Classification of the Gerri-

dae ( Hemiptera-Heteroptera ) Ryuichi Matsuda, 25

3. Serological and Chemical Studies of Gamma-irradiated

Ovalbumin,

diaries A. Leone and M. Elizabeth Wesley, 633

4. A Seasonal Survey of the Vertical Movements of Some

Zooplankters in Leavenworth County State Lake, Kan- sas Jerry C. Tosh and Kenneth B. Armitage, 657

5. The Genus Penstemon in New Mexico,

Gladys T. Nisbet and R. C. Jackson, 691

6. The Biology of Nomia (Epinomia) triangulifera with

Comparative Notes on Other Species of Nomia,

Earle A. Cross and George E. Bohart, 761

7. A Revision of the Genus Iva L R. C. Jackson, 793

8. Lung-Flukes of Snakes, Genera Thamnophis and Coluber,

in Kansas Betty Lan Stewart, 877

9. A Survey of the Periotic Labyrinth in Some Representa-

tive, Recent Reptiles Irwin L. Baird, 891

10. Observations on the Morphology of the Inner Ear in

Certain Gekkonoid Lizards David W. Hamilton, 983

THE UNIVERSITY OP KANSAS

SCIENCE BULLETIN

Vol. XLI] December 23, 1960 [No. 1

Keys to subfamilies, tribes, genera and subgenera of the Gerridae of the World'''

BY

Herbert B. Hungerford and Ryuichi Matsuda

Abstract: This paper presents keys for the identification of subgenera, genera, and higher categories of the five subfamiHes of the waterstrider family Gerridae. The groupings are as follows: Rhagadotarsinae with two genera and four subgenera; Trepobatinae with thirteen genera; Halobatinae including the tribe Halobatini with two genera, and the tribe Metrocorini with seven genera and two subgenera; Ptilomerinae with eight genera and two subgenera; Gerrinae including the tribe Cylindrostethini with three genera, the tribe Charmatometrini with three genera, the tribe Gerrini with ten genera and eight subgenera, and the tribe Eotrechini with four genera.

When we began this and the following detailed study by the junior author we had available in the Francis Huntington Snow Entomological collections of the University of Kansas eighty-nine percent of the known genera and subgenera of the Gerridae of the world. The collections also contained the types of many species described by Hungerford and his students (Anderson, Shaw, Kenaga, Kuitert), by Drake and Harris, by Kirkaldy and by Torre- Bueno. There were paratypes of species described by Drake and Harris, Esaki, China, Drake, Hussey, Usinger, Hoberlandt and a number of others. We also had specimens determined by Kiritschenko and Poisson which were most helpful.

Of the genera not represented in our collection we have been able to borrow for study representative species of seven genera through the kindness of Dr. W. E. China and Dr. E. S. Brown of the British Museum, Dr. T. Jaczewski of the Polish Academy of Sciences, Dr. P. Basilevsky of the Royal Museum of Belgian Congo, Dr. A. Collart of the Royal Institute of Natural Sciences of Belgium, Drs. A. Soos and E. Halasfy of the Hungarian National Museum, Dr. R. Poisson of the University of Rennes, France, Dr. S. Miyamoto of the Kyushu University, Japan, and Miss L. C. Chen of the National Taiwan University, to all of whom we are most grateful. Of the three genera we have not seen, the type of one has never been located at any museum ( Rheu- matotrechus himalayanus Kirkaldy).

During our studies of the Gerridae we have published many papers

* Contribution number 1,047 from the Department of Entomology, University of Kan- sas. This study was made possible with the aid of a grant from the National Science Foundation.

(3)

4 The University Science Bulletin

describing new genera, subgenera and species, raising subgenera to genera, reducing genera to subgenera or synonymizing genera so that the information could be used in reporting the present study. As we bring them to a close we recognize fifty-three genera and sixteen subgenera in the Gerridae and the possibility of at least another subgenus, a question we cannot settle with- out more material.

The keys which are given below are followed by six plates illustrating all but three of the recognized genera. There are sixty-four of these wash- drawings. The figures referred to beyond these sixty-four are to be found in the succeeding paper by the junior author ( Mori^hology, Evolution and a Classification of the Gerridae); certain page numbers also refer to the latter work. These structural drawings are useful in understanding the keys and must be studied before vmdertaking to use the keys.

Key to Subfamilies 1. Metacetabular suture in wingless forms dorsally continues to posterior margin of mesonotum, forming secondary definitive intersegmental suture between mesonotum and metanotum.* Without anteriorly produced primary intersegmental suture lat- erally in front of metathoracic spiracle (figs. 78-81, 107) .... 2

1. Metacetabular suture in wingless forms dorsally not continuous to posterior margin of mesonotum, not forming secondary de- finitive intersegmental suture between mesonotum and meta- notum ( exception Cylindrostethini * ) . Primary intersegmental suture anteriorly produced laterally in front of metathoracic spiracle, or the suture lost laterally or rarely dorsolaterally lost (figs. 72-77, 107) 3

2. First abdominal ventrite present (fig. 96)

Rhagadotarsiruie Lundblad, p. 319

2. First abdominal ventrite absent ( fig. 94 ) . . Trepobatinoe Matsuda, p. 330

3. Metacetabular suture dorsally reaching anterior end of first abdominal tergite and intersegmental suture between mesono- tum and metanotum always distinct laterally. Metacetabular region thus always appears to be divided into two areas

( figs. 72, 73 ) Ptilomerinae Bianchi, p. 260

3. Metacetabular suture not reaching anterior end of first ab- dominal tergite ( except for a few genera of Halobatinae ) . Intersegmental suture either lost laterally or rarely retained lat- erally. Metacetabular region thus never divided into two areas (figs. 74-77) 4

4. Metastermun clearly present, at least about one tenth as long

as mesostemum in length Gerrinae Amyot and Serville, p. 160

4. Metastemum represented by a very short transverse, sub- triangular plate rarely reaching metacetabular region laterally, or rarely by omphalium only Halobatinae Bianchi, p. 289

* In Cylindrostethini the metacetabular region is divided into two areas but the metacetabular suture dorsally reaches the intersegmental suture (posterior margin of mesonotum), not the anterior end of the first abdominal tergite. In the genera of Halo- batinae, in which the metacetabular suture reaches the anterior end of the first abdominal tergite, the intersegmental suture is lost laterally, thus the metacetabular region is not divided into two areas.

Key to the Gerridae of the World 5

Key to Genera of Rhagadotarsinae 1. Distal tarsal segment of front leg cleft at tip, with claws arising from base of the cleft. Eighth abdominal segment of both sexes elongate and nearly cylindrical. Males with a longitu- dinal depression on venter of seventh and eighth segments (fig. 37) Rhagadotarsus Breddin 2, p. 322

1. Distal tarsal segment of front leg not cleft at tip but claws arising preapically from beneath. Eighth abdominal segment of both sexes not elongate as described above (fig. 39)

Rhenmatohatcs Bergroth 3, p. 326

2. Pronotum in wingless forms short, one quarter the length of head. Mesothorax slightly wider than long. Hind coxae visible

from above (fig. 37) R. (Rhagadotarsus) Breddin, p. 326

2. Pronotum longer, one half the length of head. Mesothorax plainly longer than wide. Hind coxae not visible from

above ( fig. 38 ) R. (Caprivia) China, p. 326

3. Anterior femur of male may be stout but lacks tuft of stout

hairs on anterior margin R. (Rhetimatobates) Bergroth, p. 329

3. Anterior femur of male stout, with a tuft of stout hairs on

anterior margin (fig. 941) R. (Htjnesia) China, p. 329

Key to Genera of Trepobatinae 1. Hind femur distinctly longer than length of body. Second and third antennal segments swollen at distal ends and often bearing conspicuous spine clump in male. Hind tarsus with elongate, knife blade shaped claws at or before middle of second tarsal segment ( fig. 57 ) Metrobates Uhler, p. 362

1. Hind femur as long as or shorter than length of body. Second and third antennal segments witliout apical modifi- cations mentioned above. Hind tarsus with claws not as described above 2

2. Intersegmental suture between mesonotum and metanotum carinated (fig. 54) Hijnesionella Poisson, p. 359

2. Intersegmental suture between mesonotum and metanotum not carinated 3

3. First antennal segment considerably longer than second and third segments together ( fig. 52 )

Trepobatoides Hungerford and Matsuda, p. 343

3. First antennal segment at most as long as second and third segments together 4

4. First middle tarsal segment over twice as long as second middle tarsal segment 5

4. First middle tarsal segment distinctly less than twice as long

as second middle tarsal segment 6

5. Head between eyes greatly widened posteriorly in female. Eyes overlapping less than half of propleuron. Male front tibia

strongly arched, (figs. 62, 63) Rheumatometra Kirkaldy, p. 364

5. Head between eyes subquadrangular, very slightly widened posteriorly in female. Eyes overlapping most of propleuron. Male front femur and tibia not arched ( fig. 53 )

Metrobatopsis Esaki, p. 367

6 The University Science Bulletin

6. Third antennal segment over twice as long as second segment, and distinctly longer than first segment 7

6. Third antennal segment less than one and a half times as long as second, distinctly shorter than first 8

7. First antennal segment nearly straight, not reaching beyond eyes. Anterior margins of first and second abdominal tergites completely absent. Metanotum without median longitudinal

sulcus. South East Asia (fig. 51) Cryptobates Esaki, p. 355

7, First antennal segment distinctly curved near base and reach- ing behind eyes. Anterior margin of first and second tergites recognizable laterally. Median longitudinal sulcus of metano- tum normally absent (fig. 59 ) Telmatometra Bergroth, p. 340

8. Omphalium distinctly present 9

8. Omphalium absent or occasionally vestigial 10

9. Omphalium very conspicuous, located on strongly anteriorly produced anterior margin of metasternum ( fig. 58 )

Stenobates Esaki, p. 353 9. Omphalium not conspicuous, anterior margin of metasternum not strongly produced anteriorly (fig. 56)

Rhcumatometroides Hungerford and Matsuda, p. 351 10. Mesopleura without distinct longitudinal stripe (see fig. 61)

Naboandelus Distant, p. 357

10. Mesopleura with distinct black, or yellow, or brown longi- tudinal stripe 11

11. Middle tibia distinctly shorter than length of body (fig. 55)

Ovatametra Kenaga, p. 348

11. Middle tibia about as long as or a little longer than length of body 12

12. Eyes not extending beyond middle of propleura in side view. Hind tibia distinctly less than twice as long as tarsus (fig. 60 )

Trepobates Uhler, p. 337 12. Eyes extending beyond anterior half of propleura. Hind tibia

over twice as long as tarsus (fig. 50) . . Halobatopsis Bianchi, p. 346

Key to Tribes, Genera and Subgenera of Halobatinae 1. Clypeus with ba^al margin well defined, anterior margin of head not smoothly rounded. Marine in habitat

Halobatini Bianchi 2, p. 294

1. Clypeus with basal margin obliterated or lost. Anterior mar- gin of head broadly and smoothly rounded. Fresh water in

habitat Metrocorini Matsuda 3, p. 301

2. Long hairs confined to middle tibia (fig. 40 ) . Asdepios Distant, p. 297

2. Long hairs present on tibia and first tarsal segment of middle

leg (fig. 41) Halobates Eschscholtz, p. 299

3. Metanotum with lateral longitudinal elevation * reaching inter- segmental suture between mesonotum and metanotum. Male third antennal segment has stiff hairs on margins ( fig. 44 )

Esakia Lundblad, p. 316

* Appears to be forward continuation of the abdominal connexivuin.

Key to the Gerridae of the World 7

3. Metanotum with lateral longitudinal elevation not reaching intersegmental suture between mesonotum and metanotum. Male third antennal segment without stiff marginal hairs 4

4. Eyes overlapping anterolateral angles of mesonotum 5

4. Eyes not overlapping anterolateral angles of mesonotum 6

5. Posterolateral angles of metacetabula simple. Male without a tubercle either on mesosternum or on inner margin of front

femur Ventidius (Ventidius) Distant, p. 313

5. Posterolateral angles of metacetabula bilobed. Male with a tubercle on mesosternum and on inner margin of front femur

(fig. 43) Ventidius (Ventidioides) Hungerford and Matsuda, p. 315

6. Metasternum represented practically by a small omphalial pore

(fig. 48) Etirymetropsiella Poisson, p. 307

6. Metasternum represented either by a transverse subtriangular lobe, or posteriorly produced conical plate bearing omphalium, 7

7. Metasternum represented by a conical plate produced pos- teriorly (fig. 49) Eurymetropsielloides Poisson, p. 309

7. Metasternum represented by a transverse subtriangular plate,

its anterior margin more or less strongly produced anteriorly . . 8

8. Mesonotal region with a median longitudinal and lateral paired oblique black stripes 9

8. Mesonotal region predominantly black, without black longi- tudinal stripes. Male pygophore bifurcates apically (fig. 46)

Eurymetropsis Poisson, p. 311

9. Body flattened and often lustrous above. Female seventh abdominal segment with ventral apical margin simply con- cave (fig. 47) Eurymetra Esaki, p. 305

9. Body flattened and dull in color above. Female seventh abdominal segment with ventral apical margin excessively developed and modified in various shapes, hiding eighth seg- ment (fig. 45) Metrocoris Mayr, p. 302

Ke\ to Genera and Subgenera of Ptilomerinae 1. Hind tarsal segments fused 2

1. Hind tarsal segments distinct from each other 4

2. Lateral longitudinal suture of mesonotum distinct. Female abdomen withdrawn into thoracic cavity ( fig. 28 )

Potamometra Blanchi, p. 271

2. Lateral longitudinal suture of mesonotum absent. Female abdomen is not withdrawn into thoracic cavity 3

3. Hind coxa without a spine. Seventh segment of female without lateral lobes ( fig. 33 )

Ptilomera (Proptilomera) Hungerford and Matsuda, p. 270

3. Hind coxa with a spine. Seventh segment of female with conspicuous lateral lobes (fig. 36)

Ptilomera (Ptilomera) Amyot and Serville, p. 270

4. Anterior margin of head rounded. First antennal segment shorter than three following segments together (fig. 32)

Rheumatogoniis Kirkaldy, p. 283

8 The University Science Bulletin

4. Anterior margin of head not rounded. First antennal segment about as long as or longer than three following segments to- gether 5

5. First hind tarsal segment shorter than second. Female seventh abdominal segment without narrow, long and spinous process. Metanotum in female without median elevated process on hind margin 6

5. First hind tarsal segment twice as long as second. Female seventh abdominal segment with narrow, long and spinous process. Metanotimi in female with median elevated process

on hind margin Pleciobates Esaki, p. 286

6. Middle and hind tarsi with distinct claws (fig. 30)

Potamometropsis Lundblad, p. 281

6. Middle and hind tarsi without distinct claws 7

7. Hind coxa long and cylindrical, twice as long as basal width. Female abdomen telescoped into thoracic cavity and its metacetabula with a fingerlike process on inner rear margin

(figs. 34, 35) Potaniometroides Hungerford, p. 278

7. Hind coxa shorter, not cylindrical, basally broader. Female abdomen not telescoped into thoracic cavity, its metacetabula without a projecting process 8

8. Front femur without or with one or two indefinite dorso- lateral bands. Caudal margin of pronotum straight or con- cave. Mesothorax with sides converging cephalad and antero- lateral angles sloping, not prominent. Female venter nonnal

( fig. 29 ) Rhtjacobates Esaki, p. 273

8. Front femur with two dorsolateral longitudinal black bands. Caudal margin of pronotum faintly undulate, its median lobe slightly produced caudally. Mesothorax with sides nearly parallel and anterolateral angles prominent and transverse. Female venter with well-demarcated flattened area (fig. 31)

Heterobates Bianchi, p. 276

Key to Tribes of Gerrinae 1. Metacetabular suture connected dorsally with dorsal posterior margin of mesonctum (intersegmental suture)

Cylindrostethini Matsuda, p. 217

1. Metacetabular suture not connected with intersegmental suture dorsally 2

2. Anterior margin of first abdominal tergite straight

Charmatometrini Matsuda, p. 233 2. Anterior margin of first abdominal tergite bisinuate (flattened

W-shaped ) 3

3*. Pronotum prolonged primitively. Connexival spine present primitively. Apical segment of endosoma always provided with ventral plate Gerrini Amyot and Serville, p. 163

* These two characters indicate fundamental differences in evolutionary trends. For separation of the genera of Gerrini and Eotrechini, see the key to genera of Gerrinae.

Key to the Gerridae of the World 9

3*. Pronotum not prolonged. Connexival spine absent primi- tively. Apical segment of endosoma with very poorly de- veloped ventral plate or without it, and apical plate greatly developed Eotrechini Matsuda, p. 243

Key to Genera of Gebrinae t

1. Hind leg longer than middle leg 2

1. Hind leg nearly as long as or shorter than middle leg 3

2. Metasternum with omphalial groove present. Claws arising preapically. Gigantic in size (fig. 3)

Gigantometra Hungerford and Matsuda, p. 171

2. Metasternum without omphahal groove. Claws arising apically. Moderate in size (fig. 25) Eotrechus Kirkaldy, p. 249

3. Metacetabular suture reaching dorsally to intersegmental suture between mesonotum and metanotum 4

3. Metacetabular suture not reaching dorsally to intersegmental suture between mesonotum and metanotum 6

4. Body strongly flattened and short, without omphahal groove

(fig. 20) Platygerris B. White, p. 231

4. Body not flattened, cylindrical or at least not short. With omphahal groove 5

5. Abdominal spiracles located closer to anterior margins than to posterior margins of segments.** Male pygophore not rotated. Body more or less cylindrical (figs. 17, 18)

Ctjlindrostethus Fieber, p. 224

5. Abdominal spiracles located at middles of segments.* Male pygophore rotated. Body shorter ( fig. 19 )

Potamobates Champion, p. 228

6. Omphalial groove present 7

6. Omphalial groove absent 10

7. Pronotum relatively short. Mesosternum about twice as long

as metasternum ( fig. 9 ) . . Gerriselloides Hungerford and Matsuda, p. 187

7. Pronotum long. Mesosternum at least five times as long as metasternum 8

8. Middle femur longer than middle tibia 9

8. Middle femur shorter than middle tibia (fig. 23)

Brachtjmetra Mayr, p. 240

9. Pronotum with four black longitudinal stripes, marginal ones confluent posteriorly. First tarsal segment of front leg shorter

than second (fig. 22) Eobates Drake and Harris, p 242

9. Pronotum without black longitudinal stripes, concolorous brown. First tarsal segment of front leg longer than second

(fig. 21 ) Charniatometra Kirkaldy, p. 238

10. First tarsal segment of middle and hind legs shorter than second. Claws arising from near middle of second segment and conspicuous (fig. 26) Ontjchotrechus Kirkaldy, p. 251

f Rhcumatotrechits Kirkaldy is not included.

** In Potamobates thomasi Hungerford the spiracle is placed closer to the anterior margin than to the posterior margin of each segment.

10 The University Science Bulletin

10. First tarsal segment of middle and hind legs longer than second. Claws inconspicuous and arising from near apex of second segment H

11. Mesonotum with paired oblique depressions near anterior mar- gin. Paramere greatly developed ( fig. 27 )

Chimarrhometra Distant, p. 254

11. Mesonotum without paired obHque depression near anterior margm ^--

12. Hind coxa distinctly longer than wide. Pronotum not pro- longed (fig. 24) Amernboa Esaki, p. 256

12. Hind coxa shorter than wide or as wide as long. Pronotum pro- longed in most species 13

13. Hind tibia less than one fourth as long as hind femur. Male suranal plate with conspicuous spinous process on each side

(figs. 10, 11) Gerrisella Poisson, p. 189

13. Hind tibia over one-third as long as hind femur. Male suranal plate without conspicuous spinous process 14

14. Pronotum with a median black longitudinal stripe 15

14. Pronotum with a median yellow longitudinal stripe 18

15. Pronotum not prolonged ( fig. 16 )

Tenagogonus (Tenagometra) Poisson, p. 213

15. Pronotum prolonged 16

16. Rostrum with third segment not reaching onto mesosternum

(fig. 12) Tenagogerris Hungerford and Matsuda, p. 191

16. Rostrum with third segment reaching onto mesosternum 17

17. Male abdomen short, 7th, 8th and 9th segments together at least as long as four preceding segments. Male without con- nexival segment produced into triangular flattened plate or

nexival spine Tenagogonus (Tenagogonus) Stal, p. 209

17. Male abdomen not reduced, 7th, 8th and 9th segments together shorter than four preceding segments. Male 7th connexival segment produced into triangular flattened plate or spinelike

process (fig. 4) Tenagogonus (Limnometra) Mayr, p. 209

18. Mesopleuron with two large white spots. Legs and antennae in male about three times longer than in female (fig. 1 )

TenagometreUa Poisson, p. 214

18. Mesopleuron without two large white spots. Legs and an- tennae nearly equal in length in both sexes 19

19. Second antennal segment as long as or longer than third, or a little shorter than third 20

19. Second antennal segment much shorter than third (fig. 2 )

Taclnjgenis Drake, p. 202

20. Pronotum shiny in most species. Pronotum either with a median longitudinal yellow stripe and lateral short yellow stripes, or the lateral stripes alone, or with a large yellow spot alone on anterior lobe 21

20. Pronotum dull, always with a median yellow longitudinal stripe which is obliterated on posterior lobe and often with a pair of large black spots on either side of median yellow longitudinal stripe 22

Key to the Gerridae of the World 11

21. Pronotum with median yellow longitudinal stripe reaching posterior margin of pronotum and always with a pair of short concolorous lateral stripes one on either side of median longi- tudinal stripe (fig. 7) Limnogonus (Limnogonus) Stal, p. 200

21. Pronotum with a large median yellow spot on anterior lobe

(fig. 8) . . Limnogonus (LimnogoneUns) Hungerford and Matsuda, p. 200

22. First antennal segment considerably shorter than second and third segments together 23

22. First antennal segment longer than or equal to or slightly shorter than second and third segments together 24

23. Relatively broad and short species. Hind femur about as long as middle femur. Metathoracic spiracle placed more than its own length from pronotum. Pronotum not fully prolonged

(fig. 5) Etirijgerris Hungerford and Matsuda,* p. 194

23. More slender and more elongate species. Hind femur distinctly longer than middle femur. Metathoracic spiracle placed less than its own length from pronotum. Pronotum fully pro- longed (fig. 14) Gerris (Limnoporus) Stal, p. 184

24. Hind tibia about three times (never over 3.2 times) as long as first tarsal segment. First antennal segment about equal to or a little shorter than two following segments together* (fig. 13)

Gerris (Gerris) Fabricius, p. 179 24. Hind tibia at least four times as long as hind first tarsal seg- ment. First antennal segment about equal to or a little longer than two following segments together ** (fig. 15)

Gerris (Aquarius) Schellenberg, p. 175

* In E. mexicanus (Champion) the posterior lobe of pronotum is almost fully pro- longed.

** The antennal character is not satisfactory for determining New World Aquarius.

12 The University Science Bulletin

Figures 1-12

1. Tenagometrella longicornis (Poisson), female.

Length of body: 12.4 mm.

2. Tachygerris quadrilineatiis (Champion), male.

Length of body: 6.85 mm.

3. Gigantometra gigas (China), male.

Length of body: 3L9 mm.

4. Tenagogontis (Limnometra) femoratus (Mayr) male.

Length of body: 18.0 mm.

5. Eunjgerris fuscinervis (Berg), male.

Length of body: 6.4 mm.

6. Tenagogonus (Tenagogonus) albovittatus Stal, male.

Length of body: 6.55 mm.

7. Limnogoniis (Limnogonus) hyalinus (Fabricius), male.

Length of body: 8.53 mm. •8. Limnogonus (Limnogonellus) hesione (Kirkaldy), female.

Length of body: 6.15 mm. '9. Gerriselloides brachynotus (Horvath), female.

Length of body: 7.6 mm.

10. Gerrisella settembrinoi (Poisson), winged male.

Length of body: 5.2 mm.

11. Gerrisella settembrinoi (Poisson), wingless male.

Length of body: 4.5 mm.

12. Tenagogerris euphrosyne (Kirkaldy), wingless female.

Length of body: 6.4 mm.

Key to the Gerridae of the World

13

Figures 1-12

itfA'^

' V ' 2 Tochygerris quadrilineatus 3 Giganlometra glgos

I Tenagomelrello longicornis

4 Tenogogonuslimnometro)

temorotus

»/ STenogogonusCTenogogonus)^ 8 Limnogonus(Limnogonellus)

albovitlatus ' Limnogonus(Limnogonus) hesrone

hyalinus

5 Eurygerns fuscinervis

9 Gerriselloides brachynotus

1 1 Gerrisello setlemtrjnoi

12 Tenoqogerris euphrosyne

10 Gerrisello settembrinoi

14 The University Science Bulletin

Figures 13-24

13. Gerris (Gerris) thoracicus Schummel, winged female.

Length of body: 11.4 mm.

14. Gerris (Limnoporus) rufoscuteUatus (Latreille), winged male.

Length of body: 13.6 mm.

15. Gerris (Aquarius) paludum Fabricius, winged male.

Length of body: 15.1 mm.

16. Tenagogonus (Tenugometra) sp., wingless female.

Length of body: 6.1 mm.

17. Cijlinorostethus palmaris Drake and Harris, wingless male.

Length of body: 16.2 mm.

18. Cylindrostethus productus Spinola, winged female.

Length of body: 27.0 mm.

19. Potamobates unidentatus Champion, wingless male.

Length of body: 8.7 mm.

20. Phitygerris depressus B. -White, wingless male.

Length of body: 5.8 mm.

21. Charmatometra hakeri Kirkaldy, wingless female.

Length of body: 13.5 mm.

22. Eobotes vittatus (Shaw), wingless male.

Length of body: 7.5 mm.

23. Brachijmetra kleopatra Kirkaldy, wingless male.

Length of body: 8.0 mm.

24. Aniemboa fumi Esaki, wingless female.

Length of body: 4.1 mm.

Key to the Gerridae of the World

15

Figures 13-24

13 GerrislGerns) IhoracicuS

l4Ge,r,s(L,m',.porusl '^ Gerns(Ap^ri^

l6Tenagogonus

(TenagomerraJ sp.

19 Fbiomobates umdenlcrtus

23BrQchymelra kleopolto 24 Amemboo fumi

22 Eoboles vittotus

16 The University Science Bulletin

Figures 25-35

25. Eotrechus kalidasa Kirkaldy, winged male.

Length of body: 10.2 mm.

26. Omjchotrechus sakuntala, Kirkaldy, wingless female.

Length of body: 6.5 mm.

27. Cliimarrhomctra orientalis (Distant), wingless male.

Length of body: 7.2 mm.

28. Potamometra berezowskii Bianchi, wingless female.

Length of body: 16.2 mm.

29. Rhyacohates takaliashii Esaki, wingless female.

Length of body: 9.2 mm.

30. Potamometropsis tverneri Hungerford, wingless female.

Length of body: 8.2 mm.

31. Heterohates dohrandti Bianchi, wingless male.

Length of body: 7.1 mm.

32. Rheumatogonus htirmanus, Distant, wingless female.

Length of body: 6.8 mm.

33. Ptilomera (Proptilomera) himalayensis Hungerford and Matsuda, winged

male. Length of body: 10.4 mm.

34. Potamometroides madagascariensis Hungerford, wingless male.

Length of body: 6.5 mm.

35. Potamometroides madagascariensis Hungerford, wingless female.

Length of body: 5.8 mm. (as for coxa)

Key to the Gerridae of the World Figures 25-35

17

25 Eotrechus kalidasa

27Chimorrhometra orientals

29 Rhyocobates lokohoshii jQ Potamometropsis werneri

31 Heteroboles dohrandti

32 Rheumatogonus burmanus

■?-,„., /r, . ,4 r> .J 35R3tamofTietroides

33Plilomera(Proptilomera) 34 Potamometroides •^~' madogoscariensis

himatayensis modogoscariensis

18 The University Science Bulletin

Figures 36-45

36. Ptilomera (Ptilomera) iverneri Hungerford and Matsuda, winged male.

Length of body: 11.0 mm.

37. Rhagadotarsus (Rhagadotarsus) kracpelini Breddin, wingless male.

Length of body: 3.1 mm.

38. Rhagadotarsus (Caprivia) hutchinsoni China, wingless female.

Length of body: 5.4 mm.

39. Rheumatohates rileyi Bergroth, wingless female.

Length of body: 2.6 mm.

40. Aschepios apicalis Esaki, wingless male.

Length of body: 2.6 mm.

41. Halohatcs sobrirms B. -White, wingless male.

Length of body: 4.0 mm.

42. Ventidiiis (Ventidius) malaijensis Hungerford and Matsuda, wingless male.

Length of body: 3.9 mm.

43. Ventidius (Ventidioidis) kuiterti Hungerford and Matsuda, wingless male.

Length of body: 2.4 mm.

44. Esakia kuiterti Hungerford and Matsuda, wingless female.

Length of body: 2.2 mm.

45. Metrocoris strangulator Breddin, wingless male.

Length of body: 5.05 mm.

Key to the Gerridae of the World Figures 36-45

19

37 Rhogadotorsus (Rhogadotrsvfi) kroepelini

39 Rheumolobotes riteyi

38 Rtngodotreus ( Capri v lo) hutchinsoni

41 Holoboles sobrmus

4 2 Ventdiusl Ventidijs) moloyensis

43 VertidnJsWertidioided huitetli

44 Lsokia Rjiteili

4 5 Melrocoris strangulator

20 The University Science Bulletin

FiGUEES 46-54

46. Eiirtjmetropsis caraijoni Poisson, wingless male.

Length of body: 5.2 mm.

47. Eurymetra natalensis (Distant), wingless female.

Length of body: 4.9 mm.

48. Eunjmetropsiella schoiitedeni Poisson, wingless female.

Length of body: 3.8 mm.

49. Eurymetropsielloides inilloti Poisson, wingless male.

Length of body: 3.5 mm.

50. Halohatopsis platensis (Berg), wingless male.

Length of body: 3.5 mm. 5L Cryptobafes raja (Distant), wingless male, genital segments removed. Length of body: 3.2 mm.

52. Trepobatoidcs boliviensis Hungerford and Matsuda.

Length of body: 3.8 mm.

53. Mctrobatopsis flavonotatus Esaki, wingless female.

Length of body: 2.4 mm.

54. Hynesionella omercooperi Hungerford and Matsuda.

Length of body; 2.35 mm.

Key to the Gerridae of the World Figures 46-54

21

4g Eurymelropsis corayoni

49 Eurymetropsielloides milloti

47 Eurymetra natalensis

50 Holobatopsis plotensis

48 Eurymelropsiello schoutedeni

5 I Cryptobates raja

T u 1 -I 53 Metrobotopsis flovonotatus 54 Hynesionello cmercooperi

52 Trepobatoides boiiviensis

22 The University Science Bulletin

Figures 55-64

55. Ovatametra minima Kenaga, wingless male.

Length of body: 2.1 mm.

56. Rheumatometroides broxvni Hungerford and Matsuda.

Length of body: 3.2 mm.

57. Metrobates hesperius Uhler, wingless male.

Length of body: 4.1 mm.

58. Stem)bates biioi ( Esaki ), wingless male.

Length of body: 4.05 mm.

59. Tehnatometra whitei Bergrotli, wingless female.

Length of body: 4.2 mm.

60. Trepobates pictus ( Herrich-Schaeffer ) , wingless male.

Length of body: 3.3 mm.

61. Nuboamlelus bergevini Bergroth, wingless female.

Length of body: 2.55 mm.

62. Rheumatometra philarete Kirkaldy, wingless female.

Length of body: 3.15 mm.

63. Rheumatometra philarete Kirkaldy, wingless male.

Length of body: 2.3 mm.

64. Hermatobates iveddi China, wingless male.

Length of body: 3.6 mm.

Key to the Gerridae of the World 23

Figures 55-64

55 Ovotametra minima ^•^ 57 Metroboteshesperius co c. u. u-

^^ OH btenobotes biri

56 Rtieumofometroides browni

59 Telmatometfo white!

61 Naboondelus bergevini

60 Trepobotes pictus

63 Rheumotometro philorete

64 Hermotobales weddi

6 2 Rheumatomefra ptnlorete

THE UNIVERSITY OP KANSAS

SCIENCE BULLETIN

Vol. XLI] December 23, 1960 [No. 2

Morphology, Evolution and a Classification of the Gerridae (Hemiptera-Heteroptera) *

BY

Ryuichi Matsuda

The University of Kansas

Abstract: This work is a study of the morphology, evolution and classifica- tion of the Gerridae of the World. Fifty genera and sixteen subgenera out of fifty-three genera and sixteen subgenera known were examined.

In the section on morphology it is attempted to establish homologies and a tenninology for as many external structures as possible. In the section on the structural evolution the process of evolutionary change of each structure is traced, and its taxonomic significance is discussed. The postembryonic de- velopment of the antennal and leg segments has been studied in representative species of each major group to see how the different proportional lengths of antennal and leg segments are realized ontogenetically; how the ontogenetic growth patterns for these segments have been carried over to adult phylogeny; and how the growth patterns themselves have evolved. It was found that ( I ) the antennal and leg segments show roughly a simple allometric growth, with either an appreciable increase or decrease in growth ratio at the final stage of development; (2) often lengths of the leg and antennal segments of adults in a great majority of species within a genus fall roughly on the growth lines for the corresponding segments in a representative species of the same genus, indicating that species within a genus share very similar growth patterns for corresponding segments; (3) a hypothetically primitive growth ratio for the antennal segments (k = 1.142) is suggested; (4) a process of development of the proximo-distal gradient in growth ratios for the antennal segments in the phylogeny of the Gerridae is traced; ( 5 ) for certain segments, such as the hind tibia, there is evidence in many genera that the growth patterns vary among species of a genus, thus forming the secondary phylogenetic allomorphic lines; ( 6 ) as a result of the formation of the secondary allomorphic slope for the hind tibia, which is always steeper than that for the hind femur, the tibia is shorter in relation to the femur in the smaller species of a given genus, and this tendency occurs in most major groups of the Gerridae; (7) since there is a striking tendency toward smaller body size in the structurally more specialized forms at all taxonomic levels, and the congeneric species often appear to have

* The contribution number 1048 from the Department of Entomology, The University of Kansas. This study was made possible with the aid of a grant from the National Science Foundation.

(25)

26 The University Science Bulletin

very similar allometric growth patterns for corresponding antennal and leg segments, the lengths of antennal and leg segments in the early postembryonic developmental stages in larger and primitive species roughly approximate the lengths of the same in adults of related but phylogenetically more advanced forms. In the light of the knowledge gained from the study of evolution of the leg and antennal segments, the taxonomic status of all groups of the Gerridae (subfamilies, tribes, genera and subgenera) is evaluated.

The arrangement of genera in the proposed new classification of the Gerridae follows. Trepobatinae is described as a new subfamily and Hermatobatinae is excluded from the Gerridae.

( 1 ) Gerrinae.

Gerrini, including Gerris (Gerris s. str., Aquarius, Limnoporus), Gerriselloides, Gerrisella, Gigantometra, Tenagogerris, Eurygerris, Lirnnogonus (Limnogontis s. str., Limnogonellus), Tachygerris, Tenagogonus (Tenagogonus s. str., Lunno- metra, Tenagometra), Tenagometrella.

Cylindrostethini, including Cylindrostethus, Potamobates, Flaty gerris.

Charmatonietrini, including Charmatometra, Brachymctra, Eohates.

Eotrechini, including Eotrechus, Onychotrechus, Chimarrhometra, Amemboa, Rheumatotrechusi?).

(2) Ptilomerinae, including Ptilomera (Ptilomera s. str., Proptilomera), Pota- mometra, Rhyacobates, Heterobates, Potamometroides, Potamometropsis, Rheu- matogonus, Pleciobates.

( 3 ) Halobatinae.

Halobatini, including Asclepios, Halobates.

Metrocorini, including Metrocaris, Eurymetra, Eurymetropsiella, Eurymetro- psielloides, Eurymetraj)sis, Ventidius (Ventidius s. str., Ventidioides), Esakia.

(4) Rhagadotarsinae, including Rimgadotarsus (Rhagadotarsus s. str., Ca- privia), Rheumatobates (Rheumatobates s. str., Hynesia).

(5) Trepobatinae, including Trepobates, Tehnatometra, Trepobatoides, Halobatopsis, Ovatametra, Rheumatometroides, Stenobates, Cryptobates, Na- boandelus, H tjnesionella, Metrobates, Rheumatornetra, Metrobatopsis.

CONTENTS

Abstract 25

Introduction 31

External Morphology 33

The head 33

The thorax 34

The prothorax 35

The mesothorax and iving bases 35

The inetathorax 37

The abdomen 39

The pregenital segments 39

1. The first abdominal segment 40

2. The second to seventh abdominal segments 41

The genital segments 41

1. Origin of the male external genitalia in Hemiptera 41

StLTDY of the GERRroAE OF THE WORLD 27

PAGE

2. The male external genitalia of the Gerridae 43

3. Origin of the female external genitalia in Hemiptera 45

4. The structural plan of the female external genitalia in

Hemiptera, with special reference to Gerridae 45

Evolution of Structures 47

I. Evolution of the Structures Other Than the Legs and

Antennae 47

The shape of the body 47

The head 51

The shape of the head 51

The eyes 52

The chjpeus 53

The mandibular and maxillary plates and the labrum 53

The rostrum 54

The prothorax 54

The pronotum 54

The mesothorax 56

The lateral longitudinal suture of the mesonotum 56

The median longitudinal sulcus of the mesonotum 56

The mesosternum 57

The intersegmental suture between the mesonotum and

metanotum 57

The metathorax 58

The metathoracic spiracle 58

The median longitudinal sulcus 59

The lateral longitudinal suture of the metanotum 59

The metasternum 59

The omphalium 61

The first abdominal segment 61

The first abdominal tergite 61

The connexival part of the first abdominal segment 62

Tlie first abdominal ventrite 62

The second to sixth abdominal segments 63

The second to sixth abdominal tergites and ventrites 63

The location of the abdominal spiracles 64

The ventral longitudinal suture of the connexixmm 65

The seventh abdominal segment 66

The eighth abdominal segment 70

The ninth abdominal segment 72

The ninth tergite (suranal plate) in the male 72

The parameres 73

The pygophore 74

The styloide 75

The endosoma 75

The prolongation of the apical segment of the endosoma 79

The female genitalia 79

The forewing 81

28 The University Science Bulletin

PAGE

II. Evolution of the Legs and Antenna 83

1. Postembryonic development 83

Relative growth 84

Comparison of growth ratio 92

2. Evolution of the leg and antennal segments in adult phylogeny 93

The antenna 95

The hind leg 108

The middle leg 118

The front leg 123

The tarsal segments 127

TJie front tarsal segments 128

Tlie middle tarsal segments 130

The hind tarsal segments 133

The coxa 135

Phylogenetic changes in relative lengths between the middle

and hind legs 136

Shift of the position of claws 136

3. General discussion 137

Ontogeny and phylogeny 137

Taxonomic significance 139

4. Parallelism 142

Classification 152

Earher classifications 152

A new classification 154

Relationships of subfamilies 158

Subfamily Gerrinae 160

Table of significant characters 162

Relationships of tribes 161 '

Tribe Gerrini 163

Table of significant characters 165

Relationships of genera 168

Evolutionary tendencies and characters more or less peculiar

to Gerrini 170

Genus Gigantometra 171

Genus Gerris 173

Subgenus Aquarius 175

Subgenus Gerris s. str 179

Subgenus Limnoporus 184

Genus Gerriselloides 187

Genus Gerrisella 189

Genus Tenagogerris 191

Genus Eurtjgerris 194

Genus Limnogonus 197