93 



The practical inference to be drawn from the above discovery i* 

 this: — I said in my Paper on Curculios that, "by destroying the 

 wormy fruit you do not diminish the crop of Curculios for the current 

 year, but only that for the ensuing year." Hiis was stated on the 

 hypothesis of the species being single-brooded, ^^ow that we know 

 that it is double-brooded, it must be evident that, by destroying in 

 June and early in July, before the larvae have left the fruit and gone 

 underground, the wormy fruit that produces the first brood of beetles, 

 you prevent that first brood of beetles from puncturing the fruit so 

 as to generate the second brood, and consequently you do "diminish 

 the crop of Curculios for the current year." 



It is a mistake to suppose that no plum contains more than one 

 Curculio egg. 1 counted no less than five plums, that had fallen off 

 my tame Plum-tree, every one of which bore on its surface five Cur- 

 culio crescents; and in a wild Plum I once (July 38th) counted as 

 many as nine. It must not be imagined, either, that the Curculio 

 ever cuts these crescent-slits by way of food for itself. It does really 

 feed, in the perfect beetle state, on tbe flesh of the unripe plum, as I 

 ascertained by putting a number of Curculios into a bottle along with 

 some unripe plums that were unwounded by any insect. But, instead 

 of cutting a curved slit for this purpose, it gouges out with its beak 

 a gaping, hemispherical hole, varying in size from that of a radish- 

 seed to that of a small pea. I formerly supposed that it was the 

 Plum-gouger that gouged these holes; but — as will be shown below — 

 that species taps the Plum for food on an entirely different system. 



Holes in the plum, very similar to those made for the sake of 

 food by the Curculio, are likewise made by the external-feeding larva 

 of a small brown Butterfly (probably Thecla falaccr, Bdv. and Lee.,), 

 of which I bred two damaged specimens on June 15th, 1865, from 

 larvffi that fed in this manner on the plum, and had been sent me by 

 Mr. James Ferrel of Muscatine, Iowa, as "quite numerous" on certain 

 plum-trees. 



The Lakva of the Plum Curculio (Fig. 3c), when 0.07 inch long, is 4 or 5 

 times as long as wide, and of a glassy-white color with a rust-red stomach 

 occupying the middle one-half of its body, and a few pale hairs towards its 

 tail. The head is large and horny, and tinged with yellow, and the mouth 

 is rust-red, with the jaws (mandibles) large and often opening and shutting 

 in a vicious-looking manner, as with many other larvae belonging to this 

 family. 



I do not believe that there is any parasitic insect whatever that 

 preys upon the Curculio. If there had been, so many Curculios as I 

 have bred, I think that I should have met with it. Dr. Fitch, indeed, 

 has figured and described a small Ichneumon-^y under the name of 



