32 THE MEXICAN COTTON-BOLL WEEVIL. 



of the first generation which had fed upon no cotton were placed upon 

 Hibiscus militaris, and these starved within an average of three or 

 four days. The first-generation weevils which had fed for a few days 

 on squares were placed upon leaves, buds, and seed pods of Hibiscus 

 vesicarius. Though they fed a little, all starved in an average of about 

 five days. A lot of first-generation weevils, fed first for several days 

 with squares, were given leaves, buds, and seed pods of okra More 

 feeding was done by this lot than by any other, all parts being slightly 

 attacked. These weevils lived for an average of seven days. In 

 experiments conducted independently by Messrs. Tucker and Jones 

 at Alexandria and Shreveport, La., and Dallas, Tex., with II. mos- 

 chuetos, H. militaris, and H. africanus, weevils were found to feed 

 slightly on the pods, and fertile eggs were also found on the outside 

 of the pods, but none were ever placed within. 



No results whatever were obtained by experiments with a species of 

 Abutilon. In an experiment with hollyhock (Althsea sp.) three weevils 

 lived an average of six days. In experiments by Mr. W. W. Yothers 

 with buds of Callirrhoe involucrata, 42 weevils were fed for an average 

 of 5.6 days, the maximum length of life being 1 1 days. These records 

 show that the weevils may possibly be able to feed for a few days on 

 some of the other malvaceous plants and that they may even be forced 

 to oviposit, but that under present conditions they are unable to 

 sustain life or to reproduce in these plants. The maximum length of 

 life which they have been able to live on any of these plants is hardly 

 greater than they could live with sweetened water (see Table XIII). 



Unsuccessful attempts were made to cause the weevil to feed upon 

 sunflower (Helianihus annuus), bindweed (Convolvulus reports), the 

 pigweeds (Amarantkus hybridus and A. sjrinosus), the ragweed 

 (Ambrosia jjsilostachya) , and various other species of weeds and grasses 

 which occur more or less frequently around cotton fields. 



Throughout the investigations of Prof. C. H. T. Townsend in 

 southern Texas and Mexico and of Mr. E. A. Schwarz in Texas, Cuba, 

 Mexico, and Guatemala, and the observations made by the writers 

 and their associates in all the infested region of the United States, 

 every plant closely related to cotton has been most carefully watched. 

 The uniform failure to find the weevil feeding upon any other plant 

 makes it practically certain that cotton is its only food plant. Of 

 course, the insect sometimes alights upon other plants, as it does upon 

 fence posts and other objects. Such occurrences are altogether acci- 

 dental. Frequent reports of the finding of the weevil breeding in 

 other plants are due to mistaking some other insect for the enemy of 

 cotton. 



LIFE HISTORY. 



SUMMARY. 1 



The egg is deposited by the female weevil in a cavity formed by 

 eating into a cotton square or boll. The egg hatches in a few days 

 and the footless grub begins to feed, making a larger place for itself 

 as it grows. During the course of its growth the larva sheds its skin 

 at least three times, the third molt being at the formation of the pupa, 

 which after a few days sheds its skin, whereupon the transformation 



i Extract from Bulletin 51, Bureau of Entomology, pp. 30, 31. 



