130 INSECTS AFFECTING VEGETATION 



fruit will also be large in numbers. Any natural condition of 

 climate or disease that affects the mango crop will likewise reduce the 

 numbers of the mango weevil. 



The fact that the weevil during its entire development is within 

 the seed renders the use of any insecticide impossible in combating 

 the pest. Since also there is practically no exterior evidence that the 

 fruit is infested, little can be done in the destruction of infested fruit 

 during the growth of the crop. 



The destruction of all fallen mangoes and refuse seeds will be 

 quite effective for the reason that the adult beetle does not leave the 

 seed until some time after the maturity of the fruit. 



The burning, of all refuse about the mango trees during the 

 months from October to March would destroy many of the hiber- 

 nated weevils. (Press Bui. 17 Hawaii Agr. Ex. Sta.) 



THE NUT WEEVILS. 



The Larger Chestnut Weevil. The larger chestnut weevil is 

 considerably the larger and more robust species. The female 

 rostrum or beak, although proportionately of about the same length 

 as in the lesser weevil, is perceptibly more prominent because less 

 curved, the curvature being toward the tip. It is also more widened 

 at the base. The body measures from one-third to nearly one-half 

 of an inch in length, and the beak of the female is often five-eighths 

 of an inch long. That of the male is nearly as long as the elytra. 

 The egg is small, about one-sixteenth of an inch long. It is nearly 

 white, partially translucent, and without sculpture. 



The larva is milk-white, robust, fully three times as long as 

 wide, with the dorsal or upper portion rounded and convex. The 

 entire surface is very strongly wrinkled transversely, and there are 

 a few very short hairs scattered sparsely over the different segments. 

 The head is about one-fourth as wide as the widest portion of the 

 body. It is provided with short but strong mandibles, by means of 

 which it gnaws the kernel constituting its food. The fully devel- 

 oped larva in ordinary resting position measures nearly half an inch. 

 Although the larva has no true legs, it is able to crawl, slowly and 

 clumsily, it is true, by means of the flattened lower surface, locomo- 

 tion being aided by transverse wrinkles. 



The pupa is of a clearer whitish color than the larva, and shows 

 the principal external organs of the body of the future beetle, all, 

 except the beak, folded tightly to the body. 



This species, like the other weevils under consideration, is 

 native to America and is known from Rhode Island to Virginia, the 

 District of Columbia, southern Ohio, and Tennessee, and westward 

 to Kansas. The geographical distribution of this and the other nut 

 weevils has as yet not been carefully studied, but in all probability 

 it is considerably more extensive than above stated. 



In some regions this species is quite generally known as the 

 chinquapin weevil, but the investigations conducted during 1904 

 indicate that, although it breeds in chinquapins and more com- 

 monly in chestnuts, it occurs in greater abundance in the larger 

 imported nuts. 



