112 THE ORDER OF COLEOPTERA. 



The autennte, in all tlie Traclielides are of nearly or the same width 

 throughout, sometimes simple or filiform, sometimes serrate, and some- 

 times pectinate or branched, especially in the males. The elongated 

 coxaj permit great freedom of motion to the legs ; and their frequently 

 bright or diversified colors show that they live exposed to the light of 

 the sun. Accordingly we find that in their matured state they are 

 active diurnal insects, often frequenting plants and flowers. 



We have designated the insects of this tribe as parasitic heetles, a 

 title which preeminently, but not exclusively belongs to them. The 

 term parasite literally means one who sits at the table of another, and 

 lives at his expense, and is now very commonly applied to those insects 

 which either inhabit the nests of other insects and subsist upon the food 

 prepared by them, or which infest the bodies of other insects, feediug 

 upon their substance, and ultimately causing their .death. This para- 

 sitism is found to be very extensive in the insect world, and to consti- 

 tute one of the most efficient agencies by which the excessive increase of 

 many kinds of insects is kept in check. The great majority of parasitic 

 insects is found in the order of Hymenoptera, where they corajirise some 

 of the most numerous of the families of insects. In the order of Coleop- 

 tera the parasitic species are comparatively few, and outside of the pres- 

 ent tribe, are mostly limited to a small number of minute species in the 

 families Staphylinidie, Pselaphidte and Scydmtenidie. The parasitic 

 character is therefore the more distinctive of the present tribe, most of 

 the families of which are parasitic in their larva state ; though it is pret 

 ty well determined that a few of tliem are lignivorous, and the larvie 

 of some of the families are but little known. The Lagriidte and Anthi- 

 cid?e, from certain observations which have been made upon them, are 

 supposed to be carnivorous, andLatreille considered the latter to be par- 

 asitic. The Ehipiphorid?e, StyloiJhidte, and MeloidiB, including the sub- 

 family of Horiides, are known to be parasitic. The larvre of the Pyro- 

 chroidai and Mordellidie are found in wood, ui)on which, therefore, they 

 are supposed to feed. Mr. Eiley has found the Mordella 8-punctata, 

 and its larvtc, (Fig. 50) in very rotten oak stumps, and he states there 

 can be no doubt of its lignivorous habits, as he has found the larva; in 

 their own burrows, extending through the wood in all directions. He 

 has likewise bred a smaller species from the green stems of ambrosia, 

 and other herbacious plants. In a strict classification according to the 

 habits, therefore, the Pyrochroidfe and Mordellidte would require to be 

 sepiirated from the parasitic families, but there appear to be no organic 

 characters which these two families possess in common, which author- 

 izes us in placing them in a tribe by themselves. 



It is one of the many remarkable facts in the natural liistory of insects 

 that the same species often differs greatly in its habits and the nature of 

 its food, in the different stages of its existence. We have had occasion 



