THE PHEUACEOrS DIVIXG BEETLES. 



229 



447 ( ). RiiANTDs coNFrsus sp. nov. 



I'jlongate-oval, rather robust, subdepressed. Above uni- 

 form black, shining; antennae and palpi light reddish- 

 brown; tibife and tarsi dark reddish-brown; under sur- 

 face piceous. Head smooth, the front with two small 

 fovese between the bases of antennse. Thorax more than 

 twice as wide as long, sides feebly curved, margins dis- 

 tinct ; surface with sparse tine punctures near the front 

 and hind margins. Elytra each with four double rows 

 of flue, very confused punctures. Prostenium convex but 

 not distinctly carinate along the middle. Length 32 mm. 

 CSPiS- 133.) 



Floyd ('(niiity; rare. Scptenilier 'IS. Doseribed from a singles 

 male taken from beneath a .stone on the. shore of the Ohio River. 

 Tinder a strong lens the entire upper surface of both this and his- 

 Iriatus is seen to be marked with very fine reticulated lines between 

 \vlnch are nitmerous exceedingly miinite x)unctures. giving it the ap- 

 pearance of being alntaceous. 



XVIII. CoLYMBETES Clairv. 1.806. (Giv, "dive -i- swim.") 



Rather large elongate beetles having the side-; of thorax oblique, 

 not margined ; scutellum punctate ; elytra A\ith very fine transverse 

 stria}. The males have the anal segment triangularly emarginate 

 and joints 2 and 3 of front and middle tarsi clothed with small 

 equal disks. One .species occurs in Indiana. 

 448 (1474). CoLYMBETES scxjLPTiLis Harr., N. Eng. Far., 1829, 8. 



Elongate-oval. Verte.x black with two small paler spots ; 

 thorax, front of head and margins of elytra dull yellow, 

 the thorax with .i black transverse discal bar ; disk of 

 elytra darker; under surface black, legs and hind mar- 

 gins of abdominal segments reddish-brown. Length 16 mm. 

 (Fig. 114.) 



Occurs sparingh" along the .shore of Lake Michi- 

 gan ; not noted eUewhere but should occur. iMay 

 &"k^a'i.) 5-June26. 



Tribe IIL DYTISCINL 

 Diving beetles of large or medium size, easily distinguished by 

 the peculiar dilated form of the front tarsi of the males. In these 

 the first three .joints form a circular cushion with small disks on thi- 

 under side. Tlie middle tni-si are also frc(|uently dilated, the joints 

 l)cing ()l>]ong with varionsly ai-rang!>d disks oi' suckers beneath. 

 Sometimes, as in Aritkis, there are three well-marked sizes of disks 

 on the same foot. The tribe is represented in the United States by 

 six genera, five of which occur in Indiana. 



