THE AMERICAN ENTOMOLOGIST. 



the sides are ornamented with two rows of 

 black dots, and the head is black ; while 

 m juncta there is but one row of dots, and 

 the head is of a pale color, the first joint 

 behind the head reddish-brown and edged 

 with black. The mature insects differ still 

 more widely, for while lo-liiicata, as the 

 name indicates, has ten black stripes on its 

 elytra, the third and fourth stripe, count- 

 ing from the outside, are joined behind ; 

 \n Juncta, the second and third are joined, 

 and in a large proportion the two stripes 

 are united the entire length, by deep brown, 

 or black, thus forming one broad and con- 

 spicuous stripe. There are also other dis- 

 tinctive characters, shown in the accom- 

 panying figures, such as the arrangements 



[Fig. 45.] 



JoGUs Colorado Potato-bketle. — <i, a, egg.s ; b^ b, 

 larva ; f , beetle — natural size ; </, left wing cover, showing 

 punctation ; e, leg — enlarged (after Riley). 



of the punctures bordering the stripes on 

 the elytra, but these are less conspicuous 

 to the casual observer. 



A few years since, I tried to rear a 

 quantity of the larvje sent me from the 

 south on the leaves of the Potato, but 

 failed to carry a single specimen through to 

 maturity on such food. The grubs will, 

 when deprived of other and more agree- 

 able food, attack the Potato leaves, but 

 after eating a few moments, crawl away, 

 and unless supplied with more of the 

 Horse-nettle, soon die. But the genuine 

 lo-lineata is not so particular in regard to 

 its food, since the Horse-nettle and various 

 other species of Solanu?n are just as ac- 

 ceptable as the Potato, and the Egg-plant 

 {S. nielongena) is preferred to either. On 

 a pinch it will even feed on Jamestown- 

 weed {Datura), Cabbage or Smart-weed, 

 though it is questionable whether it could 

 thrive for any length of time on plants be- 

 longing to other families than that of the 



Potato. For a number of years after this 

 insect appeared east of the Mississippi, 

 there were many persons in the Western 

 States who would not believe that it was a 

 new and distinct species from the one (the 

 Doryphora juncta) that had long been 

 known as infesting the Horse-nettles grow- 

 ing on their farms and along the roadsides, 

 and even some very close observers in such 

 matters declared that their old acquaint- 

 ance had suddenly acquired a taste for the 

 Potato. But entomologists soon proved to 

 the farmers of the west that they had a 

 new foe to deal with. — A. S. F. 



( To be continued.) 



THE HESSIAN FLY.* 



HABITS AND NATURAL HISTORY. 



Number of Broods. — The Hessian Fly 

 is double-brooded, the "flaxseeds" or pu- 

 paria (Fig. 46, ^) being found on the winter 

 wheat from late in the autumn, through the 

 winter, until the early part or middle of 

 April. The " flaxseeds " of this brood, from 

 one to about twenty in number, are situ- 

 ated between the stalk and sheathing base 

 of the leaf, at the roots of the young 

 grain, slightly beneath the surface of the 

 ground. The " flaxseeds " of the second 

 generation aft'ect the wheat in the late 

 spring and summer, and are situated higher 

 up, or an inch or two above the surface of 

 the ground, at the lower joints of the 

 straw. " In the ordinary course of nature, 

 therefore," says Fitch, " our crops of winter 

 wheat are liable to two attacks of the 

 Hessian Fly, one generation reared at its 

 roots producing another, which occupies 

 the lower joints of the stalks. Thus the 

 larvce and pupae are present in it almost 

 continually, from the time the tender young 

 blades appear above the ground in autumn 

 till the grain ripens and is harvested the 

 next summer. Our spring wheat, on the 

 other hand, can rear but one brood of 

 these insects ; they consequently resort to 

 it but little, if at all. Nor can the Hessian 

 Fly sustain itself except in districts where 

 winter wheat is cultivated, in which for it 



*From advance sheeets of Bulletin No. 4, U. S. Entomo- 

 logical Commission, by A. S. Packard, Jr., M.D. 



