BEETLES. 313 



Sometimes the anteniiEe of species of this family are rendered quite ornamental by- 

 dilation of the last three joints, as in the male of J'hymaphora pukhella. 



Sub-Okdek II. — Ckyptopentameka. 



This group includes beetles which in reality have five tarsal joints, one of which 

 is abortive and hidden, giving them the appearance of having four-jointed tarsi. 



The Cheysomelid^, the so-called leaf-eaters, includes over ten thousand described 

 species, none of which reach a very large size. They attain their highest development 

 in the tropics, although found in fair numbers in all parts of the world. They- are 

 usually short-bodied, somewhat oval in outline, sometimes considerably flattened from 

 above, and often have their head more or less concealed in or beneath the forward end 

 of the prothorax. There are five abdominal segments ; the trunk is generally covered 

 by the elytra and broader than the prothorax, which latter is broader than the head. 

 Many of the species of ChrysomelidsB are brilliantly colored, some with metallic or 

 iridescent lustre. The antennae are rarely as long as the body, are eleven-jointed, as 

 a rule, but in some genera the number of joints is less. The mandibles are mostly 

 split at the tip. The legs are seldom long, and consequently their walk is slow ; wings 

 fail in a few cases, for example in Timarcha and in the females of Metacycla. 



The eggs of Chrysomelidse are laid in many cases upon the leaves or stems of 

 plants without being covered. They are usually elongated and yellowish. The first 

 brood of larvae are mostly hatched from eggs laid in spring by beetles that have 

 hibernated under bark and leaves. The larvae of Chrysomelidae vary exceedingly in 

 form and habits ; the head is small ; the body ordinarily has thirteen segments, 

 of which the three thoracic ones are always provided with legs, and are generally 

 smaller than the abdominal segments ; the prothorax of many species is distinguishable 

 by its form, color, and firm consistence of its dorsum ; the terminal segment of the 

 abdomen in many species is prolonged below to form a retractile simple or bifid 

 process which assists in locomotion, and behind which is the anus. Lacordaire 

 classified the larvae of Chrysomelidae in a way to indicate much concerning their habits 

 as well as their structure ; the following is an abstract of his divisions. First, elongated, 

 whitish, sub-cylindrical larvae, living at the base of aquatic plants (Donacia). Second, 

 larvae which cover themselves with their excrement. Short, oblong, brownish larvae, 

 without special device for carrying their excrement (JLema, Crioceris). Oval, broad, 

 spiny larvae, bearing their excrement upon a fork attached to the anal segment ( Cas- 

 sida and its allies). Third, miners. Elongated, sub-cylindrical larvae tapered at both 

 extremities {Haltica and other flea-beetles). Oblong larvae, attenuated at the two 

 ends, and having lateral warts {Sispa, Odontota). Fourth, short, thick, colored 

 larvae, generally provided with a false anal foot, often warty, and living exposed on 

 plants {Chrysomela, Doryphora, Gastrophysa). Fifth, elongated, sub-cylindrical, 

 warty, whitish larvae, curved upon themselves at their posterior end, and living in 

 cases on plants or in ants' nests {Clythra, Cryptocephalus). 



The larvae move slowly, eat parts of jjlants, usually the leaves, sometimes the roots, 

 and each sj^ecies generally confines its attacks to one kind, or at most to one family 

 of plants, both larva and imago often eating the same jjlant. Not only the larvae but 

 often the images are in many species gregarious. Birds do very little to reduce the 

 number of these larvee, many of which have disagreeable odors, while others are 

 protected by covering themselves with their own excrement, and still others are hidden 



