Middle legs closely approximated to hind pair and far 

 removed from front pair, tarsal claws and arolia of 

 middle legs modified into four broad, membranous 



plates; tropical America, Marine 



Husseyella Herring 1955 



Key to California Species of Rhagovella 



i 

 Apterous Specimens 



1. Size relatively small, 3>4 to 4 mm.; male with pronotum 

 covering all the mesonotum; female with connexiva 

 contiguous or nearly so along mid-line (fig. 7:30); 

 Blythe, California obesa Uhler 1872 



— Size larger, distinctly more than 4 mm. long; male with 

 pronotum not quite covering all the mesonotum, the 

 hind margin narrowly but distinctly exposed; female 

 with connexiva separated by a distinct gap along mid- 

 line (fig. 7:29a); generally distributed in California 



distincta Champion 1898 



Key to California Species of Microvelia 

 Apterous Males 3 



1. Pronotum extending backward over mesonotum to level 

 of sublateral pits (fig. 7:31a,6) 2 



— Pronotum not produced over mesonotum, shorter than 

 mesonotum at middle with a distinct sinuate suture at 

 hind margin which clearly reaches lateral margins 

 (fig. l:2,\c,d) 5 



2. Pronotum produced over both lobes of the mesonotum 

 leaving only the lateral triangles of the metanotum 

 showing cerifera McKinstry 1937 



— Pronotum produced over the anterior lobe of the meso- 

 notum only 3 



3. Tarsal segment of the front legs not noticeably longer 

 than segments of middle and hind legs 



signata Uhler 1894 



— Tarsal segment of the front legs noticeably longer than 

 segments of middle and hind legs 4 



4. Pronotum about 3 times as long at middle as mesonotum, 

 the hind margin of pronotum straight at middle; abdomen 

 with conspicuous tufts of silvery pubescence; color 

 black, the anterior lobe of pronotum with a pale spot; 



Corvallis, Oregon buenoi Drake 1920 



Pronotum less than twice as long as mesonotum at 

 middle, the hind margin broadly concave at middle; 

 abdomen without conspicuous tufts of silvery pubes- 

 cence; color dark brown with numerous paler areas 

 (fig. 7:31c-a'); southern California .... hinei Drake 1920 



5. Hind tibiae curved, length less than 2 mm. Corvallis, 

 Oregon (= incerta Kirby, = borealis Bueno) 



pulchella Westwood 1834 



— Hind tibiae straight, length more than 2 mm 6 



6. Hind femora inflated, 5 times as long (from apices of 

 trochanters) as greatest thickness, with several prom- 

 inent spines; hind tibiae with long hairs on apical 

 half, the individual hairs longer than thickness of 

 tibiae; apical segment of hind tarsi distinctly longer 

 than basal segment; widely distributed, western United 

 States and Central America. . paludicola Champion 1898 



— Hind femora more slender, about 7 times as long as 

 greatest thickness, with spines greatly reduced or 

 obsolete; hind tibiae with only short hairs, the individ- 

 ual hairs shorter than thickness of tibia; hind tarsal 

 segments subequal 7 



7. Front femur swollen, black in the middle region and 

 flattened on anterior or inner surface; western United 

 States gerhardi Hussey 1924 



— Front femur neither swollen, black nor flattened ... 8 



8. Body relatively short and broad, 2J£ times as long as 



217 



Usinger: Hemiptara 



broad, the last abdominal tergiU' transverse (fin. 7:: 



California californiensis McKinMrv 1987 



— Body longer and more slender, about 3 times as Long 



as broad, the last abdominal tergite longer than average 



width, sub quadrate; California, Arizona, Texas, Mexico 



, beameri McKinstry 1937 



REFERENCES 



CHINA, W. E., and R. L. USINGER 



1949. Classification of the Veliidae (Hemiptera) with a 

 new genus from South Africa. Ann. Mag. Nut. Hist., 

 (12)2:343-354. 

 DRAKE, C. J. and R. F. HUSSEY 



1955. Concerning the genus Microvelia Westwood, with 

 descriptions of two new species and a check-list of 

 the American forms. Florida Ent., 38:95-115. 

 FRICK, K. E. 



1949. Biology of Microvelia capitata Guerin, 1857, in the 

 Panama Canal Zone and its role as a predator on 

 Anopheline larvae. Ann. Ent. Soc. Amer., 42:77-100. 

 GOULD, G. E. 



1931. The Rhagovelia of the Western Hemisphere, with 

 notes on world distribution. Univ. Kansas Sci. Bull., 

 20:1-61. 

 HOFFMANN, W. E. 



1925. Some aquatic Hemiptera having only four nymphal 

 stages. Bull. Brooklyn Ent. Soc, 20:93-94. 

 HUNGERFORD, H. B. 



1920. The biology and ecology of aquatic and semi- 

 aquatic Hemiptera. Kansas Univ. Sci. Bull., 11:1-341. 



PARSHLEY, H. M. 



1921. On the genus Microvelia Westwood. Bull. Brooklyn 

 Ent. Soc, 16:87-93. 



TORRE-BUENO, J. R. de la 



1910. Life histories of North American water bugs. 



IU. Microvelia americana Uhler. Canad. Ent., 42:176- 



186. 

 1917. Life history of the northern Microvelia — Microvelia 



borealis Bueno. Ent. News, 28:354-359. 

 1924. A preliminary survey of the species of Microvelia 



Westwood of the Western world, with description of a 



new species from the southern United States. Bull. 



Brooklyn Ent. Soc, 19:186-194. 



Nymphs may be eliminated since all nymphs have 1-segmented 

 tarsi on all legs. Adults have 2 segments on middle and hind legs. 



Fig. 7:31. Microvelia hinei Drake: male, a, dorsal view; b, 

 lateral view. Microvelia californiensis McKinstry: male, c, dorsal 

 view; d, lateral view. 



