89 



and I have no doubt at all that this is the true explanation of the 

 phenomenon. The same end is attained, as we shall see hereafter, 

 but by a very different process, in the case of the Plum Gouger 

 {Anthonomus prunicida, Walsh), an insect belonging to a widely 

 distinct group of Snout-beetles. It may be added here, that the 

 "phytophagic species'' of Curculio, that I bred from the green Butter- 

 nut, makes just the same crescent-cut in the green shuck of that 

 fruit, as does the Plum Curculio in the flesh of the Plum. 



In the Paper already referred to I gave my reasons for the be- 

 lief, that the Curculio passed the winter in the perfect state. Mr. 

 Holcomb, of Cobden, South Illinois, has since assured me, that he 

 also has found the insect under the bark of his trees in the winter. 

 Still, it was difficult to believe, that beetles coming out in the middle 

 of July could live all through the winter, and until the middle of the 

 following June, so as to be able to sting the plums at that period. This 

 dithculty is now, I think, almost entirely done away with. I find 

 that there are two distinct broods of the Plum Curculio every year, 

 the first of which comes out in the beetle state, in the latitude of Rock 

 Island, from about July 19th to August 4th, and the second from 

 about August 23d to September 28th. TTie first brood of beetles, 

 which is generated by females that have passed the winter in the 

 beetle state, and have attacked the early fruit, lays in the more ma- 

 tured fruit the eggs from which proceed the second brood. The sec- 

 and brood of l)eetles comes out late in the same season, and the females, 

 at all events, if not the males, live through the winter, and repeat in 

 the succeeding season the process detailed above. Thus, as will be 

 seen at once, the Curculio differs from the Apple-worm or Codling 

 Moth (Carpocapsa pomonella, Linnaeus), which, as has been already 

 shown, is also double-brooded, in this, that the former passed the 

 winter in the perfect state, and the latter in tlie larva and pupa states. 



After I had made the above discovery, but before I had an- 

 nounced it to any one, Mr. Holcomb, of South Illinois, at a meeting 

 of the American Pomological Society at St. Louis, September 12th, 

 1867, in opposition to the contrary opinion of Dr. Trimble, the State 

 Entomologist of New Jersey, asserted his belief that in his neighbor- 

 hood there were two distinct broods of Curculio. And for this belief 

 he gave as a reason, that, in jarring his trees for Curculios, he had 

 observed that there was a particular period in the middle of the sum- 

 mer, during which no Curculios, or, at all events, but very few, were 

 to be met with, while both before and after this period they swarmed. 

 I found, in November, 1867, that many of the other fruit-growers 

 near Cobden, and perhaps all of them, agreed with Mr. Holcomb upon 



