40 



THE MEXICAN COTTON-BOLL WEEVIL. 



bloom (PI. V, e, j), and in very severe cases the boll will drop soon 

 after setting. 



After the females begin to oviposit their feeding habits become 

 quite different from those of the males. Up to this time both sexes 

 move but little, making a number of punctures in a single square; 

 but from this point we must consider the feeding habits of the sexes 

 separately. 



Males puncture the tip portion of the square not covered by the 

 calyx more often than do the females. The yellow or orange colored 

 excrement is abundant, and owing to the somewhat sedentary habits 

 of the males it accumulates often in rather large masses, so that it is 

 often possible to tell whether a square in the field has been attacked 

 by a male rather than by a female weevil. Observations made by 

 Dr. Hinds on 70 specimens under both field and laboratory conditions 

 show that for the first few days of their life the males make from six 

 to nine punctures a day, but that during their entire life they average 

 about 1.2 punctures per day and an average of 2.6 punctures per 

 square, injuring only about two squares every three days. Whether 

 in or out of doors, the activity of feeding decreases as the male 

 becomes older. 



After they begin to oviposit females seem generally to feed less 

 upon one square or in one puncture than they do previous to that 

 time. They obtain quite a considerable portion of their food from 

 the excavations which they make for the deposition of their eggs, and 

 as they show a strong inclination to oviposit only in clean or pre- 

 viously uninfested squares their wandering in search of such squares 

 keeps their punctures scattered so long as plenty of clean squares 

 can be found. When clean squares become scarce, the normal incli- 

 nation can not be followed, and the number of punctures made in 

 each square will be greatly increased. 



Table VIII is presented to illustrate the feeding activity of both 

 sexes : 



Table VIII. — Rate of making egg and feeding punctures by the l>nJl weevil. 1 



1 Modified from Bulletin 51, Bureau of Entomology, p. 52. 



