•I'lii': i'i;i:ii \('i:(Ms iti\i.\<; r.i':i;ri.KS. 235 



I'ows <ir {lisi<.s (Ml lllldcl- side. 'rh" clvtl'.-l n\' rciiKilc ;if(' cilllcf Sliioolll 

 (ii* roii<_ili. willi iiiimiic I iihcrclcs. Twk s|)cci('s jirc known I'l'din Iri- 

 (li;m;i. 



-KK) (14!KS). (Jhaimiodkui s i.ir.KHi .s S:i.v. .Tourn. I'liil. Acjul. Nat. Sci.. V, 

 1.SJ5. 100; Ibid. II. I'll. 



Slijilitly obovato. subdepresisetl. Head and thorax dull reddisli-yclluw, 

 the latter soinotiinos piceous at base; el.vtra blackisli-bi-dw ii, willi numerous 

 line yellow verniiculate marks, these sometimes forming; a yellowish mar- 

 gin; under surface reddish-brown, the legs paler. Elytra eaeh with two 

 rows of indistinet dorsal imnclures. Length ll.o 12 nun. 



Putnam and Lawreiico counties; IViMjui'iit i)i woodland ponds. 

 Anji'iist 7-Aii<>iist 12. 



-IC.l (14!»!M. (iK.UMioDKKES FAScicoLLis Ilarr.. N. Eng. F.ar.. \11. isiis. !.")(;. 



I'roadly ovate, subconvex. Head with occiput ;ind an M like mark 

 id.nck ; tlnn-ax dull yellow with a rather broad black liar on front and hind 

 margins; elytra bl.nckisli, tiiickiy marked with dull yellow dots, tiie mar- 

 gins and a very narrow sutural line yellow; under surface dull lirownish- 

 yellow. Length 13.5-14.5 mm. 



Lake and IMarion counties; scarce. IMarch 23-May 27. This 

 species is said by Sharp to be distinguished from the European G. 

 cincrois Linn, by the male having fewer disks on the front and 

 middk^ tarsi. In one male from Pine. Indiana, the middle tarsi are 

 not at all dilated. 



Tribe IV. CYBISTRINI. 



This tril)e is represented in the Lnited States by a small nitml)er 

 of large species belonging to the single genus Cijhislcr. They have 

 the spiracles veiy small ; hind legs liroad and poAverful ; their tibia' 

 short and broad, with the lower one of the two apical spurs dilated ; 

 hind claws very nne([iial. the inner ])eing obsolete or wanting in our 

 sj^ecies. The front tarsi of the males have joints 1-3 dilated into a 

 large circular disk bearing four I'ows of equal-sized cupules. In the 

 hollows behind the hind coxa^ of the males are four or five deep 

 ridges which, Avhen rubbed by a ridge on the under side of the fe- 

 mur, form a stridulating organ. 



XXIV. Cybister Esch. 1833. (Gr., ''a tumbler or diver.") 



This genus is considered a.s representing the highest and most 

 completely developed form of Dytiscid-p. One of the tive species 

 known from the United States occurs in Indiana. 



