232 



F will,')' 



-1)^ 'I' I SCI I), K. 



D. iHdrfji nails Tjiiin.. I). sKhliuthdl ifs Tier-, and /). dauricus GeW., 

 ai'c all l)i)i'i'a] spci-ics which iiia\' oi-cui' in northd'ii 

 Indiana. 



4r.-J (14!t1). Dytiscis HARKisii Kii'by, FaiiD. Bor. Amer. 

 is;?-, TG. 



I'rondly oval. Tlmrax at l»ase. apex and sides broadly 

 l)ni-<l(>red with yellow. Klylra with inari^inal stxipe nar- 

 rowed (iiily iH'.-ir apex, .-iiid with a narrow snltai>ieal eross- 

 li.ir ,is ill rcilicdiis. Abdominal segments reddish-yellow 

 in:ii-,uiiied wilh piceous. I^ength .")S-40 nnu. (Fig. 117.) 



Lake ami Marion eoiiiities; rare. -Jnno 2r). Onr 

 Fig. n7. Twotiiinis IfU^uc-it aiid hcst marked species. The Clarion (/Oiin- 

 (Affer'\vVkh:un.) tv' specimeii is in the Dnry eolleetion. 



XX. IIydatici'S Leach. 1S1(. ((ir.. "found in the water.") 



]\Ioderate sized, convex, repuhu'ly oval species having the thora.x 

 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 

 subecpial disks, the middle tarsi Ix'ing also iM'oadly dilated and with 

 i'c.uv rows of disks. Three species have been talcen in the State, 

 while another may occur. 



KEY TO INDIANA SPEf'UCS OF HYDATlCn'S. 



(/. liows of punctures on upiier face of hind tibia' distant froui one an- 

 other and parallel with outer liorder of tibia". 

 h. Above reddisli-browa : sides of thoi-ax dull yellow. 4'>'A. i-ickcs. 



hh. Above jiiceous; tlna'ax reddish with a black basal cross-liar. 

 c. Elytra each with four or live nai'row <lull yellow lines. 



4r)4. STAGNAI.IS. 



CO. lOlytra ninform piceons. the mai'giu only jialer. 



4'C). L.15VIPENN1S. 



(1(1. Rows of jtuuclnres on upper face of hind tibia* rather close together 

 and not parallel with hind niargius; tlaa-ax as in shufintlis : elytra 

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

 reaching apex. bimakginatus. 



4.".:', (147!)). riYDATicrs pickcs T.ec. New Sp. X. Amer. Col.. I, 1863, 23. 



Oval, moderately convex. Dark reddish-brc.wn ; subopaque. front of 

 head, margins of thorax and elytra iialer ; fi-ont and middle legs pale brown : 

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

 tinct. Female witli several iri'egular elongate punctures each side of mid- 

 dle of front of thorax, r.ength 11.' I.", nun. 



Lake ;uid Wells connties ; scarce. April 20-.June 25. 

 4.'i4 (1477). IIvnATicrs stagnalis Fab.. Mant. I, IDl. 



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

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



