428 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



Larva. — July 19, the larva is .10 inch loug, or less, and of a pale color. In the 

 spring when it assumes the imago state it is much larger, and differs but little from 

 other larviE belonging to this genus. 



The beetle. — In Mecas the claws differ from those of Saperda (in which they are 

 usually simple) in being feebly toothed or cleft. Body black, unspotted, cylindrical, 

 covered with short jirostrate hair, which conceals the punctures. Palpi black ; 

 antennae rather shorter than the body, and, excepting the basal joints, annulate with 

 cinereous and black. Thorax cylindric, diameters subequal. Elytra entire and 

 subacute at the tip, which is equally antennated from the suture and exterior mar- 

 gins. Length a little less than half an inch. (Say.) 



AFFECTING THE LEAVES. 



10. The streaked cottonwood leaf-beetle. 



Una scripta (Fabricius). 



Order Coleoptera ; family Chrysomelid.e. 



An abundant beetle, infesting the leaves of the cottonwood and other species of 

 Populus and of willows throughout the West to Colorado, and south to Louisiana, 



\ /} \ c "^ </ 



Fig. 157.— Streaked cottonwood beetle; a, beetle, 

 normal form ; b, c, d, e, showinj: variations. — Af- 

 ter Eilei' . 



destroying vast groves ; three annual broods; the larva peculiar from emitting from 

 the tips of its tuberculous spines a pungent milky fluid; transforming on the leaf, 

 the pupa remaining in the partially cast-off larva skin ; the beetle usually black on 

 the prothoras, with the sides yellow and the wing-covers yellowish, with three inter- 

 rupted lines of black or bluish spots. It may be destroyed by syringing the trees with 

 a wet preparation of London purple or Paris green. (Riley, Amer. Ent., iii, p. 159.) 



In 1884 fresh attentiou was called to the ravages of this beetle in 

 portions of Nebraska and Dakota, which led to the i)ublication by Pro- 

 fessor Eiley of an extended account of the insect in his report as TJ. S. 

 Entomologist for 1884, which we copy, as follows: 



During the past season the streaked cottonwood leaf- beetle has done great damage 

 in portions of Nebraska and Dakota. Appearing in enormous numbers, it has entirely 

 defoliated many thousands of trees, and has destroyed many plantations of young 

 saplings. The strip of country over which it has been particularly injurious has 

 been along the banks of the Missouri River in Dakota, as far west as its junction 

 with the Niobrara, and thence down through Nebraska to the Platte, as far w^est as 

 Dawson County. As a sample of the many communications which have been re- 

 ceived during the summer from the infested region, we introduce the following letter, 

 noticing the habits of this beetle, which was forwarded from the General Land 

 Office: 



