THE C4R0TJND T1ET5TLBS. 121 



10(i (750). Caiatih s iiin xr'i'ATUs Say, Trans. Amer. Phil. Soc, II, 1S23, 

 45 ; Ibid. II, 471. 

 Elongate-oval, Black or piteous, shining; antennsB and legs pale red- 

 dish-brown. Thorax slightly wider than long, sides broadly curved, hind 

 angles obtusely rounded, basal impressions not punctured. Blytral strise 

 deep, u<it punctured; iiilevvals convex, tlie third with two distinct punc- 

 (nres. I.eiifitli lti.5 1 1.5 nun. 



Northern half of State; scarce. Jtxne IT-August 21. 



XXXII. PLATYNUsBon. 1813. -(Gr., "fiat or depressed.") 



A large genus of black, green or bronzed beetles of medium size 

 and possessing the characters of the tribe. Palpi slender, with the 

 last two joints subequal; first, third and fourth joints of antennse 

 of about the same length. Body usually somewhat slender with 

 the elytra nearly twice as wide as the head or thorax. Thorax ver>' 

 variable in form, being either oval, cordate, square or rounded; 

 the margin sometimes barely visible. Elytra oval or oblong, some- 

 times elliptical, usually slightly sinuate at apex, sometimes almost 

 truncate ; the interval between the second and third striffi with from 

 three to seven dorsal punctures. 



The members of the genus occur beneath cover in all kinds of 

 situations, some species being found only along the margins of 

 ponds, streams and lakes, others in high, dry upland woods, and 

 still others only in sandy locations. A number are known to hiber- 

 nate as imagoes. The two papers treating of the species of the 

 United States fauna are as f oUov/s ; 



LeConte. — "Synopsis of the Species of Platynus and Allied 

 Genera Inhabiting the United States," w Proe. Phil. Acad. 

 Nat. Sei., VII, 1854, 35. 



LeConte. — "Synopsis of the North American Species of Platy- 

 nus," in Bull. Brook. Bntom. Soc., II, 1879, 43-58. 



About 90 species of Platynus have been described from the 

 United States. Of these 41 are known to occur in Indiana. Since 

 the number of species is so large, the genus in the table which fol- 

 lows is first divided into groups, and these in turn into species. 



KEY TO GROUPS OF INDIANA PLATYNfS. 



(I. Elytra oval without humeral angles; .side pieces of metathonix siMii. 



not- much longer than wide ; thorax ovate, narrowed behind, usutiUy 



strongly margined at sides. Group A. 



an. Elytra with broadly rounded humeral angles; side pieces of metathorax 



longer than wide. 



6. Hind angles of thorax not rounded. 



c. Front tarsi without .groo-\-cs. middle and hind tarsi with grooves 

 on the sides ; thorax narrowed behind. Group B. 



