322 NATURAL HISTORY OF ARTHROPODS. 



by the prosternum. No species of Clythra, properly speaking, have been found in the 

 United States, but a nearly related genus, Coscinoptera, is represented by several spe- 

 cies. The larvae of Clythra and Coscinoptera are case-bearers, and the larvse of (Jlythra 

 quadrisignata, a common European species, although normally feeding on willow, has 

 been often found in ants' nests. A part of the life-history of our most abundant species, 

 Coscinoptera dominicaiia has been described by Dr. C. V. Riley. The beetle is about 

 0.22 inch long, and is, with the exception of the yellowish brown labrum, entirely 

 black; the upper surface is densely punctate, the under side covered with ashy gray 

 pubescence. The eggs are attached in groups to plants, and each egg is borne upon 

 the end of a delicate silk-like stalk, thus resembling somewhat the eggs of the lace- 

 wing (^Chrysopa). The egg is covered, as is also the case with the eggs of most 

 species of Cryptocephalus and of ClytJn-a, with markings formed by the excrement or 

 by a secretion of the beetle. The eggs hatch in from fourteen to eighteen days, and 

 each egg-shell serves the newly hatched larva for a case, into which it withdraws on 

 the slightest disturbance. The young larva feeds on dead and decaying leaves of many 

 kinds of trees. When its case becomes too small to accommodate its increased size, it 

 cements pieces of earth upon the margins of the egg-shell, using saliva to make the 

 materials adhere. Thus a ridged case is formed, in which the larva passes its life, 

 probably requiring two years for full growth, and pupating finally in its case, after the 

 entrance of the latter is sealed up and the whole case firmly secured to some surface. 

 Chlamys, of which the larvse are also case-bearers, differs from Cryptocephalns and 

 Coscinoptera in being covered with large tuberosities, and in having grooves in the 

 flanks of the prothorax to receive the antennae. The species generally have metallic 

 coloration, sometimes dull ; some of them, including our commonest species, Chlamys 

 plicata, so closely resemble a piece of caterpillar's dung that birds would not 

 pick them from a leaf. The eggs of C. plicata are borne upon short peduncles, and it 

 has been discovered that, before they are protected by a coating of excrement or of 

 secretion by the female, they are greedily sought for and devoured by the males. The 

 larva feeds on oak, sycamore, blackberry, and sweet-fern, and inhabits a nearly smooth 

 sub-globular case, which is formed, as in Coscinoptera, by additions to the egg-shell. 

 Pupation takes place in the case, pre\iously secured to a leaf by its oral end, and the 

 imago, when about to emerge, cuts a lid from the aboral end of the case. 



Two genera, Lema and Crioceris, the latter introduced fvom Europe, represent in 

 North America another group of Chrysomelidae. The characters of this group may be 

 summed up as follows : prothorax narrower than the elj-tra, not margined ; middle ventral 

 segment not narrowed, and last dorsal segment covered by the punctato-striate elytra ; 

 presternum very narrow ; first ventral segment scarcely longer than the second. 



Lema has the prothorax constricted at the middle. The best known North Amer- 

 ican species is L. trilineata, a common potato-beetle. It has a reddish yellow head and 

 prothorax, and three longitudinal black stripes on the elyjDtra. Its 

 yellow eggs are attached to the under side of potato leaves ; they hatch 

 in about a fortnight. The yellowish larvse have their anal opening on 

 the upper side of their terminal segment, -and they cover themselves 

 with their soft, greenish excrement. At the end of about two weeks 

 Fig. 358. — Lema the larvae descend into the ground, free themselves of their excrement, 

 form an earthern cocoon with the aid of gummy matter from their mouth, 

 and pupate. Pupation lasts about a fortnight. 



Crioceris has a cylindrical prothorax. C, asparagi, the common asparagus-beetle 



