50 



can live for a long time upon leaves alone when squares and bolls are 

 wanting. Bolls are only slightly attacked so long as there is an 

 abundance of clean squares. 



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

 are very flexibly attached at the tip of the snout (fig. 2) and are 

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

 the prothorax 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. Y^hile the material 

 removed from the cavity is used for food, the 

 bulk of the feeding is upon the tender, closely 

 compacted, and highly nutritious anthers or 

 pollen sacs of the square. When these are 

 reached the cavity is enlarged, 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 (PL III, fig. 8); 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 cavities are often formed in one square (PI. VII, fig. 31), 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 con- 



Fig. 2.— Mexican cotton boll 



weevil: Head showing ros- 

 trum with antennse near 

 middle and mandibles 

 at end — much enlarged 

 (original). 



