232 



FAMILY IV. DYTlM'll'i:. 



D. marginalis Linn.. D. sublimbatas Lec. and D. dauricus Gebl.. 



are all boreal species which may occur in northern 

 Indiana. 



452 (1491). Dytiscus harbisii Kirby, Faun. Bor. Anier. 

 1837. 76. 



Broadly aval. Thorax at base, apex and sides broadly 

 bordered with yellow. Elytra with marginal stripe nar- 

 rowed only near apex, and with a narrow subapical cross- 

 bar as in verticalis. Abdominal segments reddish-yellow 

 margined with piceous. Length 38-40 mm. ( Fig. 117. I 



Lake and Marion counties ; rare. June 26. Our 

 Fi g . hi Two-third? largest and best marked species. The Marion Goun- 

 CAfttfwicSm.) ty specimen is in the Dury collection. 



XX. Hydaticus Leach. 1817. (Gr.. "found in the water.") 



Moderate sized, convex, regularly oval species having the thorax 

 not margined: prosternal spine with a rather broad oval expansion, 

 and obtuse or rounded at apex : hind tarsal claws unequal, the inner 

 one the longer. The dilated front tarsi of males bear numerous 

 subequal disks, the middle tarsi being also broadly dilated and with 

 four rows of disks. Three species have been taken in the State, 

 while another may occur. 



KEY TO INDIANA SPECIES OF HYDATICUS. 



a. Bows of punctures on upper face of hind tibia? distant from one an- 



other and parallel with enter border of tibiae 

 h. Above reddish-brown : sides of thorax dull yellow. 



453. piceus. 



hh. Above piceous; thorax reddish with a black basal cross-bar. 

 c. Elytra each with four or five narrow dull yellow lines. 



454. STAGNATES. 



cd Elytra uniform piceous. the margin only paler. 



455. E.EVIPEXXIS. 



an. Bows of punctures on upper face of hind tibiae rather close together 

 and not parallel with hind margins; thorax as in stagnates; elytra 

 with a submarginal yellow stripe, recurved at the humerus and not 

 reaching apex. bimakginatus. 



453 (1479). Hydaticus piceus Bee. New Sp. X. Amer. Col.. I. 1S63, 23. 

 Oval, moderately convex. Dark reddish-brown : subopaque. front of 



head, margins of thorax and elytra paler : front and middle legs pale brown : 

 hind legs and abdomen darker. Dorsal rows of punctures evident but indis- 

 tinct. Female with several irregular elongate punctures each side of mid- 

 dle of front of thorax. Length 12-13 mm. 



Lake and Wells counties ; scarce. April 20— June 25. 



454 (1477). Hydaticus stagnaeis Fab. ? Mant. I. 191. 



Ovate, subconvex. Above piceous: thorax and front of head reddish- 

 vellow. the former with a curved black basal cross-bar which does not reach 



