840 FAMILY XLI. MALACH1ID/10. 



tips. From the Lampyrida; they are distinguished chiefly by hav- 

 ing the antennae inserted upon the front at the sides, generally be- 

 fore the eyes ; by the presence of a separate piece between the labrum 

 and the front and by the fourth joint of the tarsi not being bilobed. 

 The great majority of our Indiana species also have the power of 

 protruding from the sides of the abdomen a number of soft, orange- 

 colored vesicles which are supposed to bo s<-ent organs used in 

 defense. 



In addition to the characters mentioned, the Malaehiidse have 

 the mentum small, quadrate and horn-like; antenna' 11-jointed, 

 usually serrate and often curiously knotted in the male; head ex- 

 serted and prolonged into a short, broad beak; elytra usually en- 

 tire, sometimes slightly abbreviated; abdomen with six free ventral 

 segments; prosternum short, not extending between the front coxa', 

 which are large, conical, contiguous, with distinct trochantins, the 

 coxal cavities large, transverse, open behind; tarsi 5-joiuted, fili- 

 form; claws usually with a large membranous appendage between 

 them. 



The larva? of the Malachiidae are, so far as known, carnivorous. 

 The mature insects occur on flowers or herbage, some only in low, 

 moist places, and are said to feed on insect eggs, larvae and small, 

 soft-bodied insects, so that on the whole they may be classed as 

 beneficial. 



The principal literature treating of the genera occurring in 

 Indiana is as follows: 



LfCniifi. "Catalogue of the Melyrides of the United States, 

 with Descriptions of New Species,'' in Froc. Phil. Acad. 

 Sci., VI, 1852, 163-171. 



Horn. "Synopsis of the Genus Collops," in Trans. Amer. 

 Entom. Soc., Ill, 1870, 79-84. 



Horn. "Synopsis of the Malachiida 3 of the United States," in 

 Trans. Amer. Entom. Soc., IV. 1872. 109-127. 



Casey. "Synopsis of the Meivrida? of North America," in Ann. 

 N. Y. Acad. Sci., VIII, 1895. 456-606. 



About 140 species, distributed among 20 genera, are listed by 

 Henshaw from the United States, most of them inhabiting the 

 region west of the Rocky Mountains. 



KEY TO THE INDIANA GENEEA OF MALACHIIDAE. 



a. Sides of body with extensible vesicles, the front pair proceeding from a 

 fissure beneath the front angles of the thorax ; last joint of tarsi with 

 two membranous appendages beneath the claws. 

 It. Antenna? apparently 10-jointed. I. COLLOPS. 



