730 REPORT UNITED STATES GEOLOGICAL SURVEY. 



eyes. Antennae and head in front yellowish ; tipper lip (labrnm) black ; both pairs of 

 palpi redclisb-brown. Prothoras yellow, especially on the binder edge, and tiujjed with 

 brown on the sides and in the middle. Wing-covers black, each with a broad yellow 

 longitudina-l stripe ouo-half as wide as the wing-covers. Body beneath black. Legs 

 yellowish, tinged with brown on the hind femora, which are much swollen, and be- 

 come paler toward the tip. Length, 0.18 inch, or nearly two lines. The species has 

 been identified by Dr. Horn. 



The Three-Lined Potato- Beetle, Lema trUineofa, (Olivier. Plate LXVI, Figs. 4, 

 5.) — Thick-bodied grubs, much smaller than those of the Colorado beetles, feeding on 

 the leaves and disguising themselves with their own escremtnt, becoming black beetles 

 striped with yellow, and with a reddish head and prothoras. 



This beetle need not be coufounded with the Colorado beetle, as it is 

 about half the size of the latter, and is only occasionally destructive in 

 the Eastern States, especially New England. The beetle is black, striped 

 with yellow, with a reddish head and prothorax. The grub or larva is 

 a soft-bodied, thick grub, but slenderer than that of Doryphora. It 

 conceals itself by covering its body with accumtilations of its own ex- 

 crement. It matures in two weeks, and transforms in the ground, the 

 beetle appearing about the 1st of August. Hand-picking in the early 

 part of July is a sufiicient remedy. 



Blistering Beetles, Epicauta cinerea Fabricins (Plate LXVI, Fig. 6) ; E. macrohasia 

 mtirina LeConte; atrata Fabricius (Fig. 7); ^./aftncii LeConte (Fig. fc).— Long, slen- 

 der, gray, striped or spotted, or black beetles, with a prominent head, feedmg on the 

 leaves, and sometimes even more detstructive than the Colorado beetle. 



These beetles are allied to the Spanish fly, and, like that insect, all 

 secrete the blistering substance called " cautharadine." 



The gray blistering beetles (Plate LXVI, Fig. 6) in Massachusetts 

 appear, according to Harris, about the 20th of June, and sometimes do a 

 great deal of mischief. In the night-time and in rainy weather they leave 

 the plants and burrow at the roots for shelter, and eat in the morning 

 and evening. 



Common as these insects are in the beetle state, the larva of some of 

 our native species have not yet been discovered, and the only informa- 

 tion available to me is a brief account of the young of the European 

 Spanish fly Lytta vesicatoria in Westwood's Modern Classification of 

 Insects, where it is stated that thelarvrelive underground, feeding upon 

 the roots of vegetables. " They have the body soft, and of a yellow- 

 ish-white, composed of thirteen segments, with two short filiform au- 

 tennse, and six short, scaly feet." 



While the gray blisteriug beetle is common northwards, the black 

 species, U. ijensylvanica, is equally or more so, while E. cinerea (Forster) 

 (Plate LXVI, Fig. 8,) is more common southward, and E. vittata (Plate 

 LXVI, Fig. 9) is very destructive in potato-fields in the Middle, Western, 

 and Southern States. 



Epicauta pennsylvanica is perhaps onr commonest species northward, and is totally 

 black, and slightly smaller than E. cinerea ; it is black, but ash-colored on the head 

 and prothorax and on the under side of the body. It occurs as far west as Kansas. 

 (E. vittata is longer and slenderer than the others named, and is clay -yellow, with six 

 lilack longitudinal stripes.) 



Macrobasis muria is found west as far as Northern New Mexico, and 

 is to be looked for in Colorado and Wyoming. 



The following is Fay's description : " Lake Superior, two males. 

 Easily distinguished by its more sparse pubescence ; the thorax is 

 shorter, more convex, and more narrowed anteriorly, and the upper sur- 

 face is more distinctly punctured ; theantennse are one-half the length of 

 the body, the first joint reaching the occiput, the second joint equal to 

 thetwo'followiug. With this species I doubtfully associate a female 

 from Missouri Territory, agreeing in form and punctation, in which the 



