45 



SYNOPSIS OF THE N. A. SPECIES OF PLATYNUS, Bon. 



By John L. Leconte M.D. 



A. — Elytra oval, without humeral angles ; metathoracic side- 

 pieces short, not much longer than wide. Prothorax ovate, nar- 

 rowed behind, strongly margined at the sides. Pubescence of 

 antennae beginning on 4th joint. 



a. — Front tarsi with medial grooves on upper surface ; hind and middle tarsi 

 with lateral grooves. Hind angles of prothorax well defined. 

 Elytra obliquely sinuate at tip, sutural points divergent ; color brown ; 

 legs and antennae paler. Rhadine, Lee. 

 Third joint of antennae much longer than fourth. 



Sutural angles less acute. 1. larvalis. 



" " very acute and divergent. 2. caudatus. 



Third joint of antennae but little longer than fourth ; sutural angles less 

 acute, slightly divergent. 3. dissectus. 



b. — Front tarsi without grooves, middle and hind tarsi with lateral grooves. 

 Platynus, auct. 

 Front tarsi of male very narrow, 1st joint much longer. 2. 



" " " wider, 1st joint not much longer. 4. 



2. — Front tarsi with terminal spur large ; striae of elytra fine, impunctured ; 

 sutural tips divergent, not acute ; color entirely black ; hind angles 

 of prothorax not rounded. 4. jejunus. 



Front tarsi with terminal spur fine ; hind angles of prothorax rounded ; 

 striae of elytra deep. 3. 



3. — Antennae and legs ferruginous ; alternate interspaces of elytra with num- 

 erous punctures. 5. hypolithos. 

 Antennae and legs black ; 3d interspace of elytra with 4 punctures. 



6. angustatus. 



4. — Smaller, brown, hind angles of prothorax not rounded, elytral striae fine, 



3d interspace with 3 punctures ; tips of elytra feebly obliquely sinuate 



7. agilis. 



B. — Elytra with broadly rounded humeral angles ; side-pieces of 

 metathorax longer than wide : prothorax narrowed behind, hind 

 angles usually not rounded ; pubescence of antennae beginning 

 on fourth joint ; front tarsi without grooves, middle and hind 

 tarsi with lateral grooves. 



Wings wanting ; elytra scarcely sinuate behind, sutural angles sepa- 

 rately rounded. 2. 

 Wings well developed. 3. 



Bull. Br'klyn Ent. Soc. October, 1879. 



