THE STATE ENTOMOLOGIST. 107 



Thus, these two beetles differ essentially from one another upon a 

 strict comparison; but the general resemblance is so great that it is 

 not to be wondered at that the two have been confounded together 

 by several otherwise well qualified observers. 



Habits of the Colorado Potato-beetle. — This insect can fly, 

 though it does so very reluctantly and only during the heat of the 

 day. Its wings, like those of several allied species, are of a bright 

 rose-color, and with its cream colored body, and the five black stripes 

 upon each wing case, it presents a beautiful appearance as it flies 

 abroad in the clear light of the sun. Its transformations were first 

 made known by myself in the Prairie Farmer for August 8, 1863- 

 Subsequently, in 1866, Dr. Shinier, of Mt. Carroll, detailed some addi- 

 tional particulars bearing on its habits, in a paper which he published 

 in the Practical Entomologist (vol. 1, pp. 84-85). In the latitude of 

 St. Louis there are three broods during the year, the last brood win- 

 tering over in the beetle state underground. They are usually dug 

 up in the spring of the year in land that had been planted to potatoes 

 the year before. The beetles issue of their own accord from the 

 ground about the first of May, and the last brood of beetles enters the 

 ground to hybernate during the month of October. Though, in gen- 

 eral terms, this beetle may be said to be three-brooded, yet it may be 

 found at almost any time of the year in all its different stages- 

 This is owing to the fact that the female continues to deposit her eggs 

 in patches from time to time — covering a period of about forty days; 

 and also from the fact that among those larvas which all hatch out in one 

 day, some will develop and become beetles a week and even ten days 

 earlier than others. Thus it may be that some of the late individuals 

 of the third brood pass the winter in the pupa state, though the nor- 

 mal habit is to first transform to beetles. Each female is capable of 

 depositing upwards of a thousand eggs before she becomes barren, 

 and in from thirty to forty days from the time they were deposited, 

 they will have produced perfect beetles. These beetles are again 

 capable of depositing eggs in about two weeks after issuing from the 

 ground, and thus, in about fifty days after the egg islaid, the offspring 

 begins to propagate. The pupa of the Colorado Potato beetle is re- 

 presented at Figure 46, c. It is formed in a little cavity which the 

 larva had made perfectly smooth and hard, and it is of the same color 

 as the larva. The beetle, on first emerging from it, is quite p.-ile and 

 soft, without any markings whatever. 



Unlike many other noxious insects, this larva is not a general 

 feeder, but is confined to plants belonging to the potato family (Sola- 

 nacece), and especially to the genus to which the potato belongs 

 (Solamim). Occasionally it feeds on the tomato, on the'ground-cher- 

 ry ( Physalis), and on the imported Jamestown-weed, or gympson- 

 weed (Datura). Itprefers the horse-nettle (Sola?ium carolinense) to 

 some varieties of the potato, and were it not that the nettle is con- 

 sidered a nuisance, on account of the difficulty of eradicating it when 



