208 FAMILY IV. DTTISCID.E. 



an. Last Joint of imixillMry imlpus trimcntp: proiJtprnal prni^pss verj bmarl 

 behind the rcix:e: hind tibi;« broader; length 4-5 mm. 



II. Htdbocanthu.s. 



]. ("'anthydrus Sharp. LSS2. (Gr.. "beetle + water.") 



Small and short, strongly convex species, usually variegated in 

 color above; antennae very short and slender; pectoral plate coarsely 

 sculptured at middle; hind legs slender, the femora and tibiae but 

 little flattened, the former contiguous at base. Two species occur 

 in the State. 



393 (1237). C.4?iTHYDKUs BicoLOR Say. Trans. Amer. Phil. Soc. IV. 1834. 

 -MT : ibid. II, 561. 

 Ovate, convex. Head, thorax and under parts reddish-yellow ; elytra 

 dark reddish-brown, thickly and rather coarsely punctate. Length 2.5 mm. 



A small but handsome species, taken in Indiana only from Bass 

 Lake, Starke County, and Hudson Lake. Laporte County. Prob- 

 ably occurs throughout the lake region of the State. 3Iay 30- Au- 

 gust 20'. 



,394 (1238). C.-vNTHYDKrs gibbulus Aubg, Spec. Gen., YI. 1838. 414. 



Ovate, convex. Head and thorax yellow, the latter clouded with dusky 

 on the front margin ; elytra dark brown or picei:>us. with an irregular oblique 

 .vellowish cross-bar near the middle. Elytra more sparingly punctate than 

 in iicolor, the dorsal rows of punctures more distinct. Length 2.5 mm. 



Beneath rubbish on beach of Lake ^Michigan, near Pine. Lake 

 County: scarce. August 1. 



II. HYDEOC.VNTHrs Say. 1.823. Mir., "water -■- beetle. "") 



In addition to the characters given in the ke.v. this genus may be 

 known by having the last .ioint of the labial palpus very large, tri- 

 angular and compressed; the front tibife with a strong spur; the 

 hind femora short and stout, their apical margins strongly ciliated; 

 tibia' short, smooth, claws equal. But one snerde^ is Iniown from the 

 United States. 



305 fl240). Hydhoc.vnthus iricolor Sny, Trans. Amer. Phil. Soc\. II. 1823. 

 lOo; ibid. II, 517. 

 Ovate, convex, attenuate behind. Head, thorax and under parts red- 

 dish-yellow; elytra dark I'oddish-brown, polished, iridescent. Three in-ei-oi- 

 lar dorsal rows of fine punctures visible. Length 4-5 mm. 



Throughout the State ; frequent. ^Fareh 16-August 15. Prob- 

 ably hibernates, as one was taken from mud at the liottom of a pond 

 on the earlier date. 



