840 FAMILY XIJ. — MALACHHD/i;. 



tips. From the Lampyridas they are distinguished chiefly liy hav- 

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

 fore the eyes ; by the jjresence 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 be scent organs used in 

 defense. 



In addition to the characters mentioned, the Malachiidas have 

 the inentum small, quadrate and hcni-like; antenna' 11-jointed, 

 usually serrate and i.»ftcn curiously knotted in the male ; head ex- 

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

 tire, sometimes slightly abbreviated; abdomen with six free ventral 

 segments; presternum short, not extending between the front coxae, 

 \vhich are large, conical, contiguous, with distinct trochantins, the 

 coxal cavities large, transvei'se, open behind; tarsi 5-jointed, fili- 

 form; clav.s usually Avith a large membranous appendage between 

 them. 



The larva? of the ilalaehiidffi 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, larva and small, 

 soft-bodied insects, so that on the ^\■hole they may be classed as 

 beneficial. 



The principal literature treating of the genera occurring in 

 Indiana is as follows : 



Lc'C'onte.—" Catalogue of the IMelyrides of the United States. 



with Descriptions of New Species," in Proc. Phil Acad 



Sci., VI, 1852, 163-171. 

 J/orH.— "Synopsis of the Genus Collops." in Trans. Amer 



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

 Horn.— "Synopsis of the .Malachiida> of the United States." in 



Trans. Amer. Entom. Snc. IV. ]S72. ] 09-127 

 CV(.se.(/.—" Synopsis of the lleiyrida^ of North .\merica," in Ann 



N. Y. Acad. Sci., VIII, 1895. 45(1-606, 

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

 I-Ienshaw from the United States, most of them inhabiting the 

 region west of the Rocky Atountains. 



KEY TO THE INDIANA GENERA OF .\[.\LACHIID^. 



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

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

 two membrnn.ius appendages beneath the claws 

 h. Antennas appai'ently 10-jointeil ' , ,^ 



I. Ooixops. 



