18 



BULLETIN 61, UNITED STATES NATIONAL MUSEUM. 



a b c d 



Fig. 32.— A lacewing fly, Chrysopa: a, Eggs; 6, larva; 

 c, cocoons; d, fly with left wings removed. 



Beetles pass through a complete metamorphosis. The larvae show 

 great variety in shape and structure, but are often elongate, rather 

 flat creatures, with or without legs, and with strong biting jaws. The 

 pupa shows the legs and antennae of the adult folded against the body, 

 and the wing-pads are applied to the sides. Several arrangements of 

 the beetles in large groups or sections have been proposed by coleop- 



terists, yet none of such strik- 

 ing superiority as to command 

 general adoption. In Europe, 

 Professor Kolbe and Doctor 

 Ganglbauer have proposed 

 new systems of Coleoptera, 

 which have many valuable 

 points; however, a slight 

 modification of the arrange- 

 ment used by Doctors Le Conte and Horn is as useful, and probably 

 as natural, as any other. It divides the beetles into seven sections, 

 as follows: 



Adephaga. — The antennas are simple, not with leaflike plates nor 

 enlarged at tip; all the tarsi five-jointed. The mouth-parts are 

 usually well developed, and the abdomen shows six segments on the 

 under side. The larvae are usually very active and commonly pre- 

 daceous. They have a tapering body, widest near the middle, with 

 prominent head and jaws, prominent legs, ending in two claws, and 

 frequently one, two, or three terminal processes or tails to the body. 

 Many of the species are aquatic (Dytiscidae, fig. 128). Others are 

 called ground-beetles (figs. 33, 127) and 

 tiger-beetles. The tiger-beetles (fig. 129) 

 (Cicindelidse) are usually of very brilliant 

 coloration, but most of the beetles (Cara- 

 bidae) of this section are black or at least 

 without particular markings. 



Clavicornia includes those beetles with 

 the antennae enlarged at the tip (fig. 123). 

 This section comprises a great number of 

 species, usually of small size, but of great 

 diversity of structure and habit. The 

 tarsi in most of the families are five- 

 jointed, but many of the smaller species have but three-jointed 

 tarsi. The head is commonly much smaller than the thorax, and 

 often bent under or partly depressed. Most of their larvae are 

 predaceous, but many feed on dead animals or vegetable matter, 

 stored foods, in ants' nests, and a few on living plants. The larvae 

 exhibit very diverse characters, but usually they are more cylindrical 

 than those of the Adephaga and with less prominent legs, and when 

 there are terminal processes or tails they are less long than in 

 the Adephaga. To this section belong the prettily spotted ladybird 



Fig. 33.— A ground-beetle, Calo- 

 soma calidum : a, Larva; 6, adult. 



