1000 FAMILY XXXII. — VELIID.E. 



middle of mesosternum ; pro- and mesonota in one piece, in 

 winged form with front portion declivent, hind one broadly 

 triangular with apex rounded ; elytra, when present, reaching 

 tip of abdomen ; connexivum reflexed, rather widely exposed ; 

 legs rather stout, subequal in length ; front tarsi with joints 1 

 and 2 very short; middle and hind ones with joints longer, 

 cylindrical. 



Three species are known from the eastern states. They live 

 amongst the roots of grasses, in bunches of decaying weeds and 

 beneath other cover, more often on the ground near stagnant 

 water than on its surface. The eggs are deposited on floating 

 aquatic plants, floating sticks or other debris just beneath the 

 surface of the water. In one species (/'. watsoni), kept in cap- 

 tivity by Hoffman, they hatched in 12 days. The average span 

 of nymphal life was 27 days, and adults remained alive for 

 nearly two years. They were found to be both predaceous and 

 cannibalistic, feeding not only on one another but upon various 

 forms of living, crippled or dead insects placed upon the sur- 

 face of the water, as well as on small animals swimming be- 

 neath the surface film. Many nymphs were reared to maturity 

 on a straight diet of cockroaches. The specific names of two 

 English species are current and rivulosum, denoting that they 

 there live in running streams rather than ponds and lakes. 



KEY TO EASTERN' SPECIES OF VELIA. 



«. Middle and hind tarsi subequal in length, the former with joints 2 



and 3 subequal; head not immersed in thorax to eyes; form slender. 



6. Antenna? with joint 2 one-fourth shorter than 3; hind margin of 



pronotum (brachypterous form) without a fringe of long hairs; 



tubercles on sides of pronotum scarcely evident. 



1138. STAGNALIS. 



6.6. Antenna? with joints 2, 3 and 4 subequal in length; hind margin of 

 pronotum with a fringe of long hairs; tubercles on sides of prono- 

 tum very distinct. 1139. watsoni. 

 aa. Middle tarsi distinctly longer than hind ones, the former with joint 

 2 much longer than 3 ; head immersed in thorax to eyes ; form 

 robust. 1140. BRACHIALIS. 



1138 (1313). Velia stagnalis Burmeister, 1835, 212. 



Elongate, slender, sides subparallel. Brownish-yellow or tan-brown; 

 legs paler brown mottled with dull yellow; under surface with a broad 

 blackish stripe extending from prosternum to sixth ventral. Basal joint 

 of antenna? feebly curved, stouter and one-third longer than any of the 

 others, 2 shortest, 3 and 4 subequal, very slender. Eyes smaller than in 

 brachiulis. Pronotum finely, densely pilose, posterior portion coarsely 

 punctate, its hind margin narrowly rounded. Length, 4 — 4.2 mm. 



