Beetles 251 



hatch larvae usually called grubs, with three pairs of legs (sometimes want- 

 ing), with biting mouth-parts, simple eyes, and inconspicuous antennas. 

 These larvae are predaceous, as the water- tigers (larvae of water-beetles), 

 plant-feeders, as the larvae of the long-horns, or carrion-feeders, as those of the 

 burying-beetles, and so on. They grow, moult several times, and finally change 

 into a pupa either on or in the food, or very often in a rough cell under- 

 ground. From the pupa issues the fully developed winged beetle, which 

 usually has the same feeding-habits as the larva. The special food-habits 

 and characteristics of development are given for numerous common species 

 in the accounts (postea) of the various more important families of the order. 



The enonomic status of the order Coleoptera is an important one. So 

 many of the beetles are plant-feeders, and are such voracious eaters in both 

 larval and adult stages, that the order must be held to be one of the most 

 destructive in the insect class. Such notorious pests as the Colorado potato- 

 beetle, the two apple-tree borers, round-headed and flat-headed, the "buffalo- 

 moth" or carpet-beetle, the wireworms (larvae of click-beetles), the white 

 grubs (larvae of June beetles), rose-chafers, flea-beetles, bark-borers and 

 fruit- and grain-weevils, are assuredly enough to give the order a bad name. 

 But there are good beetles as well as bad ones. The little ladybirds eat 

 unnumbered hosts of plant-lice and scale-insects; the carrion -beetles are 

 active scavengers, and the members of the predaceous families, like the 

 Carabids and tiger-beetles, undoubtedly kill many noxious insects by their 

 general insect-feeding habits. 



The great order Coleoptera is divided into two primary groups, some- 

 times called suborders, namely, Coleoptera genuina, the typical or true 

 beetles, including those species in which the mouth-parts are all present and 

 the front of the head is not elongated into a beak or rostrum, and the 

 Rhynchophora, snout-beetles (p. 294), which have the front part of the 

 head more or less extended and projecting as a beak or rostrum, and the 

 mouth-parts with the labrum (upper lip) so reduced as to be indistinguish- 

 able and the palpi reduced to mere stiff jointless small processes. To 

 this latter suborder belong those beetles familiarly known as weevils, bill- 

 bugs, bark-beetles, and snout-beetles. 



KEY TO SECTIONS AND TRIBES OF COLEOPTERA GENUINA. 



With five tarsal segments in all the feet (with rare exceptions). Section PENTAMERA. (p. 252). 



With the antennae slender, thread-like, with distinct, cylindrical segments. 



(Carnivorous beetles.) Tribe ADEPHAGA (p. 252). 

 With the antennae thickened gradually or abruptly toward the tip. 



(Club-horned beetles.) Tribe CLAVICORNIA (p. 258). 

 With the antennae serrate or toothed (these serrations very slight in many cases). 



(Saw-horned beetles.) Tribe SERRICORNIA (p. 265). 



With the antennae composed of a stem-like basal part, and a number of flat blade-like 

 segments at the tip. (Blade-horned beetles.) Tribe LAMELLICORNIA (p. 272). 



