*32 FAMILY IV. BTTlSnil,!!:. 



D. marfjinalis Linn., D. subliiitbatiia Lee. and D. dauricus Gebl., 

 are all boreal species which may oei-nr in northern 

 Indiana. 



452 (1491). Dytiscus hakbisii Kirby, Faun. Bor. Amer. 

 1S37, 76. 

 Broadly oval. 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- 

 ]>ar as in rcrticaUs. Abdominal segments reddish-yellow 

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



Lake and .Marion counties; rare. June 26. Our 

 Fig. 117. Two-thirds largest End best marked species. The ^Marion C'oun- 



natural size. , • • - , i -r^ t i , • 



(After wiciiiiam.) tv Specimen IS m the Dury collection. 



XX. Hydaticus Leach. 1817. CGr., "found in the water.") 



^Moderate sized, convex, regularly oval species having the thorax 

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

 and olrtuse 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 IXDIAN.V SPECIES OF HYDATICUS. 



a. Rows of punctures on upper face of hind tibire distant from one an- 

 other and parnllel with outer border of tibifp. 

 h. Above reddisU-brown ; sides of thorax dull yellow. 453. picEUS. 



hi). -Vli.ive piceous: thorax rcdilish with a black basal cross-bar. 

 ('. Elytra each with four or five narrow dull yellow lines. 



4.54. STACiA'.MIS. 



re. Elytra uniform piceinis. the nuirgin only paler. 



455. L.EVU'KNNIS. 



(Id. Kows of punctures on upper face of hind tibiae rather close tojiclher 

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

 with a submarginal yellow stripe. rec\irved at the humerus and not 

 reaching apex. bimaeginatus, 



453 (1470). Hydaticus piceis l.ec. New Sji. X. Amer. Col.. I, 1863, 23. 

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



head, margins of thorax and elytra paler; fnuit 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 W(>l]s counties; scarce. April 20-.Tune '25. 



454 (1477). HvDATicus st.vgnalis Fab., JIant. I, 191. 



ovate, suboonvex. Above piceous; thorax and front of head rwldish- 

 yellow. I he former with a curvcil bla(4i; b.isnl cross-bar whi(4i does not roarh 



