322 NATURAL HISTORY OF ARTHROPODS. 



by the prosternum. Xo species of Ch/thra, jiropeily sjieakiuj;-, have been found in the 

 Unitecl States, but a nearly relateil genus, C'uscinoptera, is rej)resented liy sevei-al spe- 

 cies. The hirvie of Clijthra and UosciJioptera are case-bearers, and the hirvie of Cli/thra 

 quadrisignata, a coininou European species, althougli normally feeding on willow, has 

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

 Coscinoptera dominicanu has been described by Dr. C. V. Kiley. The beetle is about 

 Q.2'1 inch long, and is, with the e.xception of the yellowish brown labrum, entirely 

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

 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 (Chri/sojM). The egg is covered, as is also the case with, the eggs of most 

 species of Cryptocephalus and of t'h/thnt, with marliings 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 .-nid decaying leaves of many 

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

 cements pieces of earth ujxju 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 uji and the whole case firmly secured to .some .surface. 

 Chlami/s, of which the larvae are also case-bearers, differs from Cfi/ptocephdhfs and 

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

 flanks of the prothorax to receive the antenna;. The sjiecies generally have metallic 

 coloration, sometimes didl; some of them, including our commonest species, C/ihvni/s 

 plicata, so closely resemble a jiiece of caterpillar's dung that birds wonld not 

 pick them from a leaf. The eggs of C ]jlicata are borne upon short jieduneles, and it 

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

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

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

 sub-glol)idar case, which is formed, as in Coscinopfent, by additions to the egg-shell. 

 Pupation takes jilace in the case, previously 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, JLrma and Cn'occn'.'^, the latter introduced from Europe, rejiresent in 

 North America another group of Chrysomelida;. The ch.araeters of this group maybe 

 summed up as follows : prothorax narrower than the elytra, not margined ; middle ventral 

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

 prosternum very nari'ow ; first ventral segment scarcely longer than the second. 



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

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

 prothorax, and three longitudinal black stri])es on the elyptra. Its 

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

 in about a fortnight. The yellowish larvre have their anal o]iening on 

 the upjier side of their terminal segment, and they cover themselves 

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

 Fig. .3.i.s. — /,/.»!« the larva; descend into the ground, free themselves of their excrement, 



trUineata. .,,.-» I'l- i 



form an earthern cocoon with the aid oi gummy matter trom I heir moutli, 

 and pupate. Pujiation lasts aliout a fortnight. 



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



