SEASONAL HISTORY. 



39 



food, but is cast aside. Weevils are ready to begin feeding very soon 

 after they escape from the squares or bolls in which the previous 

 stages have been passed. For several days thereafter both sexes 

 feed almost continuously. They much prefer squares, but in con- 

 finement will feed upon leaves, flowers, or bolls. Under natural 

 conditions any portions of the plants other than the squares and bolls 

 are seldom attacked. The bolls are only slightly attacked so long as 

 there is an abundance of uninfested squares. 



1 The method of feeding is alike in both sexes. The mouth parts 

 are very flexibly attached at the tip of the snout (fig. 4) and are 

 capable of a wide range of movement. The head fits smoothly into 

 the pro thorax like the ball into a socket joint and is capable of a con- 

 siderable angle of rotation. The proboscis itself is used as a lever in 

 prying, and helps to enlarge the puncture through the floral envelopes 

 especially. Feeding is accomplished by a combination of movements. 

 The sharply toothed mandibles serve to cut and tear, while the rota- 

 tion of the head gives the cutting parts an auger-like action. The 

 forelegs especially take a very firm hold upon the square and help 

 to bring a strong pressure to bear upon the proboscis during certain 

 portions of the excavating process. The 

 outer layer of the square, the calyx of the 

 flower, is naturally the toughest portion that 

 the weevil has to penetrate, and only enough 

 is here removed to admit the snout. After 

 that is pierced the puncture proceeds quite 

 rapidly, combinations of chiseling, boring, 

 and prying movements being used. While 

 the material removed from the cavity is used 

 for food, the bulk of the feeding is upon the 

 tender, closely compacted, and highly nutri- 

 tious anthers or pollen sacs of the square. 

 When these are reached the cavity is en- 

 larged, and as much is eaten as the weevil 

 can reach. The form of the entire puncture 

 becomes finally like that of a miniature flask. 



Only after weevils have fed considerably 

 do sexual differences in feeding habits begin 

 to appear; from this time on the females puncture mainly the base 

 and the males the tip of the square. 



Feeding punctures are much larger and deeper than are those made 

 especially for the reception of the eggs; more material is removed 

 from the inside of the square or boll and the opening to the cavity is 

 never intentionally closed. Feeding punctures are most frequently 

 made through the thinner portion of the corolla not covered by the 

 calyx. The exposed tissue around the cavity quickly dries and turns 

 brown from the starting of decay. As a number of these large cav- 

 ities are often formed in one square (PL V, c), the injury becomes so 

 great as to cause the square to flare immediately, often before the 

 weevil has ceased to feed upon it. Squares so severely injured fall 

 in a very short time. The injury caused by a single feeding puncture 

 is often overcome by the square, which continues its normal course 

 of development. When feeding punctures are made in squares which 

 are nearly ready to bloom, the injury commonly produces a distorted 



Fig. 4 



Cotton-boll weevil: Head, 

 much enlarged, showing rostrum, 

 with antennae near middle and 

 mandibles at end; mandible, 

 more enlarged, at right. (Orig- 

 inal.) 



i The following four paragraphs are borrowed from Bulletin 51, Bureau of Entomology, pp. 50, 51. 



