122 FAMILY IT. OARABID.B. 



cc. All the tarsi with distinct grooves on the sides; hind angles of 

 thorax obtuse or rectangular. Group C. 



bl). Hind angles of thorax much rounded, i-arely obtuse or somewhat de- 

 fined. 

 d. Side margins of thorax wider toward the base and reflexed; tarsi 

 with distinct lateral but no medial grooves. Group D. 



lid. Side margin of thorax narrow, but little if at all reflexed. 



c. Dorsal punctures of elytra three ; thorax rounded-oval, its basal 

 impressions punctiform ; pubescence of antennse beginning on 

 fourth joint. Group E. 



ce. Dorsal punctures 4 to 6; basal impressions not punctiform; 

 pubescence of antennae beginning on third joint; thorax oval, 

 margin narrowly reflexed. Group F. 



Group A. 

 The species of this group are of a slender form, without inner 

 ^vings or with feeble ones in quadrimaculatus ; legs and antenna 

 long; thorax usually elongate; elytra regularly elliptical without 

 distinct humeral angles, sinuate toward the tip and with the lateral 

 margin broader and more reflexed than in the other groups. Four 

 species whose range is such as to include Indiana belong to this 

 group. 



KEY TO SPECIES OE GROUP a. 



«. Suture of elytra prolonged and divergent at tips; front tarsi with 

 medial grooves on upper surface. 197. CAUDATts. 



aa. Suture of elytra not prolonged at tips ; front tarsi without grooves. 

 &. Hind angles of thorax rounded ; elytral striae deep. 



c. Alternate intervals of elytra with numerous punctures ; antennae 



and legs pale reddish-brown. 198. htpolithus. 



cc. Third interval of elytra with four punctures; antennae and legs 



black. ANGUSTATUS. 



66. Hind angles of thorax rectangular; striae of elytra shallow; thorax, 

 base of elytra and subapieal spot yellow. 



199. QUADRIMACULATUS. 



197 (755). PiATYNUs CAUDATUS Lec, Xew Sp., I, 1863, 7. 



Elongate, narrow. Dark reddish-brown ; antennae and legs paler. Third 

 joint of antennae nearly twice as long as fourth. Thorax elongate-ovate, 

 side margins strongly reflexed, hind angles obtuse. Elytral margin strongly 

 reflexed, obliquely sinuate near apex ; striae almost obsolete ; alternate in- 

 tei-vals with an irregular row of rather large shallow punctures. Length 

 12.5 mm. 



Vigo and Lawrence counties ; very rare. ^lay 17-May 25. Oc- 

 curs beneath rubbish or flat stones near water. 



198 (759). Plattnus hvpolithus Say, Trans. Amer. Phil. Soc., II, 1823, 



59 ; ibid. II, 482. 

 Elongate, slender, large for the genus. Black, shining; legs and an- 

 tennae pale reddish-brown. Thorax one-half longer than wide, narrowed 



