662 



FAMILY XXVIII. TROGOSITIPiE. 



The name of the typical genus, Trogosita, derived from two 

 Greek words meaning "to gnaw" and "corn or grain," was given a 

 common European species which occurs in great numbers in worm- 

 infested granaries. Recent observations, however, go to show that 

 its larvae probably live upon the larva? of more injurious insects 

 which do the real damage to the grain. The larvae of the members 

 of the principal genus, Tenebroides, are whitish flattened grubs with 

 a pair of black spots on the top of each of the first three segments, 

 and with the last segment ending in two horny points. That of T. 

 corticaria was observed by Le Baron to feed upon the larvae of the 

 coddling moth. 



The only paper treating of the family is that of 



Horn. — "Monograph of the Species of Trogosita (Tenebroides) 

 Inhabiting the United States," in Proc. Phil. Acad. Nat. Sci., 

 1862, 82-88. 



It embodies but one of the nine genera among which the 30 or 

 more known species from North America are at present distributed. 

 Three of these genera are known to be represented in Indiana, while 

 members of four others may occur. 



KEY TO INDIANA GENERA OF TROGOSITIDiE. 



a. Form elongate, margins not flattened ; head relatively large, eyes not 

 prominent ; front coxal cavities closed. 

 1). Eyes rounded. Nemosoma. 

 bl>. Eyes transverse. 



c. Tibiae with spines; form cylindrical. I. Alindria. 



cc. Tibia? without spines. 



d. Thorax truncate at apex, the side margin bent downward at mid- 

 dle. Trogosita. 

 del. Thorax emarginate at apex, the side margin not bent downward. 



II. Tenebroides. 



aa. Form oval, margins flattened; head small, eyes prominent; mentum 

 transverse, emarginate ; front coxal cavities open behind, except in 

 Calitys. 



e. Mentum transverse, emarginate ; antennal grooves feeble. 



f. Front tibia? with terminal hook. Peltis. 

 //. Front tibia? without terminal hook. 



g. Front coxal cavities closed. Calitys. 

 gg. Front coxal cavities open behind. III. Grynocharis. 



ee. Mentum minute, oval; antennal grooves deep; front tibia? without 

 hook. Thymalus. 



Nemosoma cylindricum Lee, linear, cylindrical, black, the base 

 of elytra, antennae and legs reddish, length 4.5 mm., has been taken 

 near Cincinnati. 



