188 



Usinger: Hemiptera 



— Head shorter, not exceeding the combined length of 

 pronotum and scutellum; nymphs with a single dorsal 

 abdominal scent gland opening 13 



13. Tarsi 2-segmented in adults; under surface of head 

 deeply grooved to form a rostral sulcus (figs. 7:35; 

 7:36) HEBRIDAE 



— Tarsi 3-segmented in adults; under surface of head 

 without a rostral groove, the base of rostrum clearly 

 visible 14 



14. Legs with scattered stiff black bristles; winged forms 

 with scutellum exposed and double, and ocelli present; 

 wingless adults with scutellum and ocelli absent (figs. 

 7:37; 7:38) MESOVELUDAE 



— Legs without scattered, stiff black bristles; adults 

 fully winged or brachypterous, with scutellum concealed 

 by backwardly projecting plate of pronotum; ocelli 

 distinct (fig. 7:34) MACROVELIIDAE 



15. Ocelli close together, nearer to each other than to eyes; 

 antennal segments all about equally thick or apical 

 segments thicker (figs. 7:40; 7:41); nymphs with 1 

 dorsal abdominal scent gland opening .... SALDIDAE 



— Ocelli widely separated, nearer to eyes than to each 

 other; first 2 antennal segments very stout, the apical 

 2 slender; nymphs with 3 or 4 dorsal abdominal scent 

 gland openings (fig. 7:43) DIPSOCORIDAE 



REFERENCES 



(Sometimes cited but not repeated in later sections) 



ABBOTT, F. A., and J. R. de la TORRE-BUENO 



1923. In W. E. Britton, Guide to the insects of Connecti- 

 cut. Paxt IV, The Hemiptera or sucking insects of 

 Connecticut, pp. 1-807, 20 pis. 

 BLATCHLEY, VV. S. 



1926. Heteroptera or true bugs of eastern North America. 

 Indianapolis: Nature Publ. Co., pp. 1-1116. 

 BUTLER, E. A. 



1923. A biology of the British Hemiptera — Heteroptera. 

 London: H. F. and G. Witherby. pp. viii + 682. 



CHINA, W. E. 



1955a. The evolution of the water bugs. National Insti- 

 tute of Sciences of India, Bull. 7:91-103. 

 19556. A reconsideration of the systematic position of 

 the family Joppeicidae Reuter, with notes on the 

 phylogeny of the suborder. Ann. Mag. Nat. Hist., 

 (12)8:353-370. 

 COMSTOCK, J. H. 



1887. Note on respiration of aquatic bugs. Amer. Nat., 

 21:577-578. 

 HERRING, JON L. 



1950-1951. The aquatic and semiaquatic Hemiptera of 

 northern Florida. Part I: Gerridae. Florida Ent., 

 33:23-32; Part U: Veliidae and Mesoveliidae. Florida 

 Ent., 33:145-150; Part HI: Nepidae, Belostomatidae, 

 Notonectidae, Pleidae and Corixidae. Florida Ent., 

 34:17-29; Part IV: Classification of habitats and keys 

 to the species. Florida Ent., 34:146-161. 

 HUNGERFORD, H. B. 



1920. The biology and ecology of aquatic and semi- 

 aquatic Hemiptera. Kansas Univ. Sci. Bull. Vol. II, 

 341 pp., 31 pis., 3 color pis. (Whole Series, Vol. 21, 

 No. 17). 



1924. Stridulation of Buenoa limnocastoris Hungerford 

 and systematic notes on the Buenoa of the Douglas 

 Lake region of Michigan, with the description of a 

 new form. Ann. Ent. Soc. Amer., 17:223-227. 



JACZEWSKI, T. 



1937. Allgemeine Zuge der geographischen Verbreitungen 

 der Wasserhemipteren. Arch, fur Hydrobiol., 31:565-591. 

 KIRKALDY, G. W. 



1898-1908. A guide to the study of British waterbugs. 

 Entomologist, 31:177-180, 203-206; 32:3-8, 108-115, 

 151-154, 200-204, 296-300; 33:148-152; 38:173-178, 

 231-236; 39:60-64, 79-83, 154-157; 41:37. 



KLOET, G. S., and W. D. HINCKS 



1945. A check list of British insects. Stockport. 483 pp. 

 MACAN, T. T. 



1939. Notes on the migration of some aquatic insects. 



Jour. Soc. Brit. Ent., 2:1-6. 

 1941. A key to the British water bugs, with notes on 

 their ecology. Freshwater Biol. Assn. Brit. Emp., Sci. 

 Publ. No. 4, pp. 1-36. 

 PIERCE, W. D. 



1948. Fossil arthropods of California. 15. Some Hemiptera 

 from the McKittrick asphalt field. Bull. So. Calif. 

 Acad. Sci., 47:21-33. 

 POISSON, R. 



1924. Contribution a l'etude des Hemipteres aquatiques. 

 Bull. Biol. France et Belgique., 38:49-305, 35 figs, 

 pis. 1-13. 



SINGH-PRUTHI, HEM 



1925. The morphology of the male genitalia in Rhynchota. 

 Trans. Ent. Soc. London, pp. 127-267, 32 pis. 



THORPE, W. H. 



1950. Plastron respiration in aquatic insects. Biol. 

 Reviews, 25:344-390. 

 UHLER, P. R. 



1884. Order IV. Hemiptera. in Standard Natural History, 

 Vol. II, pp. 204-296. 

 VAN DUZEE, E. P. 



1917. Catalogue of the Hemiptera of America north of 

 Mexico. Univ. Calif. Publ. Ent., 2:1-902. 

 ZIMMERMAN, E. C. 



1948. Insects of Hawaii. Vol. 3. Heteroptera. University 

 of Hawaii Press, pp. 1-255. 



Family CORIXIDAE 



Water Boatmen 





Water boatmen are the most numerous of all aquatic 

 Hemiptera, both in species and in individuals. They 

 occur from below sea level (Death Valley, California) 

 to 15,000 feet elevation (Himalaya Mts.). They seem 

 equally adapted to the cold waters of the subarctic 

 and to tropical waters. 



Corixids play an important role in aquatic com- 

 munities because they are primary converters of 

 plant material (see below under feeding habits) and 

 also serve as an early link in the animal food chain 

 by scooping up and ingesting small benthic organisms. 

 Other food consists of small midge and mosquito 

 larvae, and to this extent corixids act as typical 

 predators. 



Analyses of fish stomachs show that corixids are 

 a preferred food in many instances (Forbes, 1888). 

 The experiments of Popham (1941) show clearly that 

 the resemblance of corixids to the immediate back- 

 ground colors of their environment is owing to selec- 

 tive predation by fish. But to what extent the bugs 

 are rendered unpalatable by their nymphal and adult 

 scent glands is not known. 



Stridulation was first recorded in the Corixidae 

 more than one hundred years ago. Several persons 

 have heard a chirping sound while observing the 

 insects in aquaria. According to Von Mitis (Hunger- 

 ford, 1948), "Only those species in which the males 

 are equipped with a field of pegs on the base of the 

 front femur are capable of producing sound, and the 

 sound is produced by rubbing this peg field over the 



