486 



FAMILY XII. TRICHO'PTERYGIDJE. 



KEY TO INDIANA GENERA OF TRICHOPTERYGIME. 



(/. Elytra entire. 



b. Thorax widest at base. 



c. Pygidium invisible ; form oval, very convex ; color dark. 



I. Nossidium. 



cc. Pygidium visible beyond the elytra ; bind angles of thorax not 

 elongate; form elongate; color pale. Nanosella. 

 hi). Thorax widest before the base. 



d. Pygidium visible beyond the elytra. Ptilium. 

 dd. Pygidium invisible. II. Ptenidium. 



a a . Elytra truncate. 



e. Antennae very short, 9-jointed; eyes wanting; thorax larger than 

 elytra. • III. Limulodes. 



ee. Antenna? elongate. ll-jointed. 

 /. Thorax widest at the base. 



g. Abdomen with seven ventral segments. Pteryx. 

 gg. Abdomen with six ventral segments. 



//. Hind coxae very widely separated; mesosternum scarcely cari- 

 nate; color pale. Ptineleodes. 

 hh. Hind coxae moderately separated; mesosternum distinctly cari- 

 nate. IV. Trtchopteryx. 

 //. Thorax widest before the base. 



/. Elytra long; mesosternum carinate ; color dark. V. Smicrus. 

 ii. Elytra short ; mesosternum not carinate. 



j. Body opaque ; abdomen moderate ; hind coxae with plates. 



Nephanes. 



,/./. Body translucent ; abdomen very long ; color pale. 



VI. Ptinella. 



I. Nossidium Erichs. 1845. (Gr., " nest + formed. " ) 

 Small oval, convex species having joints 1 and 2 of antennae very 

 large, 3-8 slender, 9-11 much thickened; abdomen with seven seg- 

 ments, entirely covered by elytra ; metasternum not reaching the 

 sides of the body. One of the two known species occurs in the 

 State. 



934 (2914). Nossidium americanum Mots., Bull. Mosc, 41, 1868, 191. 



Oblong-oval, very convex. Head and thorax 

 piceous, strongly shining ; elytra reddish-brown, 

 rather thickly clothed with long yellowish hairs ; 

 legs and antennae yellow. Thorax more than 

 twice as wide as long, hind angles rectangular ; 

 sides rounded, distinctly margined, surface very 

 finely and sparsely punctured. Elytra not wider 

 than thorax, surface with rather deep, rugose 

 punctures in sinuate transverse rows ; tips broad, 

 much rounded. Length 1 mm. (Fig. 173.) 



Monroe County ; frequent. May 13-Junc 

 9. Taken by sifting debris of beech stump. 

 Fig. 173. x 34. (Original.) Probably occurs throughout the State. 



