36 



ness ol' iho jsomsoii, toji^etlior willi tlu^ full-l'iMl condition of tho weevils, 

 Meemed to i)roniist^ m considerably longer jiei-iod tlum (1 days. 



In tlie thii-(l series tlie 18 weevils used were 1 niontli old and full- 

 fed at tho Ix^ginning of the test in the middle of November. The con- 

 ditions in this series were as in the series preceding, with the excep- 

 tion that an abundance of two species of grass taken from cotton 

 fields was included. These weevils showed an average length of life 

 of nearly 7^ days, ranging from 3 to 10 days. Tho weevils made no 

 effort to feed upon the grass, so tli<^ slightly longer life period must 

 bo due to other causes. 



CANNIBALISM. 



It is hardly proper to speak of cannibalism as a food habit of the 

 boll wci^vil, but the facts observed may well be recorded hei-(^ Under 

 tlie impulse of extreme hunger weevils have several times showed a 

 slight (^annibalist ic tendency. 



S(wen beetles were confined in a pill box without food. On the 

 third day <> only were alive. Of the s(iventli only the hardest chitin- 

 ized parts (head, proboscis, pronotum, legs, and elytra) ri^mainod, the 

 softer i)arts having been eaten by the survivors. 



In anothei" box containing 12 adults tlu^ leaf sui)plie(l for food was 

 insudicienli, and on the fourth day 8 were dead, 4 were i)artly eaten, 

 and others had lost one or more h^gs each. 



In another case a few young adults and a number of s<piai'es con- 

 taining pupje wer(^ placed in a box togetluM- with a few fri^sh squares 

 to serve as food for the adults. When the box was oi)ened after a 

 number of days, one "reddish-bi-own " adult, was found having its 

 (>lytra eaten tlirough and most of its abdomen devoured. In spite of 

 this mutilation the victim was still alive and kicking slowly. The 

 squares were still fresh and fit for food, so that this is really the clear- 

 est case of cannibalism observed. 



Frequently moi-e than one larva hatches in a s<iuare, and whentliis 

 is the cas(^ a struggle between them is a! most. c(M-tain to take jilace 

 before they be(H)me full gi'own. Many cases have been observed in 

 which S(puires contained one living and one or more smallei- dead 

 larvae, while in a few cases the actual deatli struggle was observed. 



HABITS. 



Among tlio habits of any insect of economic importance, the first 

 for careful study ai'o those relating to its food, and secondly those 

 coniuicted witli its propagation. Tlu^ study of the life history of the 

 boll weevil has revealed no especially vulnerable point, but ratlier the 

 important fact that in all its stages it is better protected against the 

 attacks of enemies and the ordinarily effective remedies recommended 

 by tlie economic entomologist than any other insect which has ever 

 threatened the production of any of tlie great staple crops of tliis 



