134 SECOND KEPORT OF THE STATE ENTOMOLOGIST. 



retractile tubercles which, serving as prolegs, aid in locomotion. When 

 full grown the larva measures three-tenths of an inch in length and 

 about one-half as broad. 



The Beetle. 



The beetle is represented, in enlargement in Fig. 33. It is about one- 

 fourth of an inch long by one-eighth of an inch broad. Its sides are 

 parallel, with its upper and lower surfaces convex. The antennae are 

 brownish-black, eleven-jointed, and about half as long as the body. The 

 head is nearly as wide as the thorax and pale yellow; the eyes 

 black and projecting, having behind them a transverse groove. 

 The thorax is as wide as long, constricted in the middle, and 

 marked with two black dots, one on each side of the middle, 

 which are sometimes quite conspicuous.* The wing-covers 

 Ttfree h^ed"ifeaf- ^^^ yellow with three parallel black stripes, viz.: one at the 

 LmEATxi'^'''^ ™' meeting of the covers, which narrows toward their tip and 

 hardly reaches it, and a broader one almost upon the outer border of each 

 cover. Intermediate to the stripes are several lines of delicate punctures. 

 The legs, which are short, are yellowish-red, and the four-jointed feet are 

 black. 



Life-History. 

 The life-history, summarized from the careful and detailed account 

 given by Dr. Fitch, is the following : 



The insect hibernates in its beetle state, and probably resorts to 

 forests for shelter.f Coming abroad in May, they feed sparingly upon 

 such vegetation as may be agreeable to them, until about the middle of 

 June when the potato leaves are sufficiently advanced to furnish them 

 with food, and place for the deposit of their eggs. The yellow, oval eggs 

 are laid in clusters of ten or more, usually upon the underside of the 

 leaves. They hatch in about a fortnight. The young larvae feed in 

 company side by side, either at the tip or on one of the margins of the 

 leaf, but as they approach maturity, they distribute themselves over the 

 leaves. Having attained their growth, they descend from the plants 

 and enter the ground for pupation, where the larva constructs a cell, 

 which it lines with a frothy secretion proceeding from its mouth, in such 

 a quantity as to entitle it to the name of a cocoon. 



*A variety occurs in which there is ati additional black spot intermediate to the two ordi- 

 nary ones, named var. tripunda, by Fitch. The original description of Fabricius, from ma- 

 terial credited to the Cape of Good Hope, and of Olivier, give three thoracic spots. 



tProf. Riley, in his 1st Missouri Report (as cited), represents the insect as hibernating in 

 the pupa state — " staying in the ground all winter, and only emerging at the beginning of 

 the following June." But Dr. Fitch had found the beetle in a torpid state, on the surface 

 of the ground under boards on the 20th of April. 



