SEASONAL HISTORY. 55 



The observations show that 86.7 per cent of all squares attacked 

 received eggs. It may also be seen that 40.9 per cent of all squares 

 oviposited in received only one egg each. The squares which were 

 only fed upon formed but 13.2 per cent of the total number attacked, 

 and, as has been shown above, those receiving both egg and feeding 

 punctures constituted 40.3 per cent. As the weevil injury overtakes 

 the production of squares the proportion of squares containing both 

 egg and feeding punctures increases rapidly. Where several eggs are 

 placed in a square it is rarely the case that more than one larva 

 develops. 1 If two or more hatch in a square one is likely to destroy 

 the others when their feeding brings them together. Should eggs be 



E laced in squares which already contain a partly grown larva, those 

 atching would probably find the quality of the food so poor that they 

 would soon die without having made much growth. Since one egg 

 will insure the destruction of the square and a number of eggs would 

 do no more, it is plain that the possible number of offspring of a single 

 female is increased directly in proportion to the number of her eggs 

 that she places one in a square. Favorable food conditions for the 

 larva are likewise best maintained by the avoidance of feeding upon 

 squares in which eggs have been deposited and also by refraining from 

 ovipositing in squares which have been much fed upon. Selection of 

 uninfested squares is, therefore, of the greatest importance in the 

 reproduction of the weevil, since this insures the most favorable con- 

 ditions for the maturity of the largest possible number of offspring. 

 Feeding and oviposition are common in the same boll, but unless 

 the infestation is very heavy it appears that only rarely is more than 

 one egg placed in one lock, though several are often deposited in the 

 same boll. The number deposited depends considerably upon the 

 size of the boll. The smallest, which have just set, receive but one, 

 as do the squares, and these fall and produce the adult weevil at about 

 the same period as in the case of squares. Bolls which are larger 

 when they become infested have often been found to be thickly punc- 

 tured and to contain 6 or 8, and in one case 15, larvae. (See PI. VI, d; 

 PI. VII, c.) 



During the fall of 1902 a series of experiments, lasting for 12 weeks, 

 was made to determine the length of life of weevils fed solely upon 

 leaves. In one lot, consisting of nine males and eight females, the 

 average length of life of the females was 25 days, while that of the 

 males was 36 days. Though this period far exceeded the normal 

 time usually passed between the emergence of adults and the begin- 

 ning of egg deposition, no eggs were found. Dissection of the females 

 which lived longest showed that their ovaries were still in latent 

 condition, though the weevils were then 81 days old. Few instances 

 of copulation were observed among weevils fed upon leaves alone, 

 and among nearly 70 weevils which were thus tested no eggs were 

 ever deposited. After a period of three weeks upon leaves, 11 weevils 

 were transferred to squares. Females in this lot began to lay in 

 four days, and four of them deposited 323 eggs in an average time 



i In one case four normal pupse were found in a single square. This observation was made at Shreveport, 

 La., by Mr. H. Pinkus. 

 8 From Bull. 51, Bureau of Entomology, pp. 112, 113. 



