BIBEBNATIOS EXPERIMENTS IN SMALL CAGES. 33 



has made some very pertinent observations on the occurrence of 

 boll weevils in cot ion mv<I intended for planting." In January, L903, 

 this entomologist examined a number of sacks of seed received from 

 the infested area of Texas for plant ing in t he 1 jaguna region in Mexico. 

 Six sacks from one consignment were selected. In these, 12 living 

 weevils were found, together with 56 dead ones. Later examinations 

 were made of a number of shipments of seed from the infested por- 

 tions of the United States. In every case living weevils were found. 

 This work was done in the month of January. These observations 

 show clearly the real danger that exists in the shipment of cotton 

 seed from infested localities to those where the weevil does not occur. 



HIBERNATION EXPERIMENTS IN SMALL CAGES. 



In many ways it is possible to obtain more accurate data, upon 

 hibernation of weevils through cage experiments than through held 

 observations. In the cages conditions may be prepared which are 

 typical of those to be found in the fields. The number of weevils 

 within a given space can be largely increased without overcrowding, 

 so far as the possibility of their finding shelter is concerned. The 

 action of the weevils in seeking and in leaving shelter can be deter- 

 mined more accurately in cages than in the field. The food condi- 

 tions may be varied to represent various field conditions and, finally, 

 knowing definitely the number of weevils placed under certain con- 

 ditions, it is possible to follow them closely enough to determine with 

 a great deal of accuracy the proportions surviving. From a com- 

 parison of the results obtained under various experimental condi- 

 tions those conditions which are most favorable as well as those which 

 are least favorable to successful hibernation may be determined with 

 considerable certainty. In all of our experimental work of this nature 

 the cage results have been checked so far as has been possible by 

 field observations. 



With the continued study of the boll-weevil problem the necessity 

 for increasingly comprehensive experiments upon hibernation has 

 become apparent. The work thus shows from year to year a growth 

 in complexity with the constant purpose of increasing the accuracy 

 of results by making the experimental conditions conform as closely 

 as is possible to field conditions. In the early stages of the work the 

 hibernation cages were small and portable. Some were placed out 

 of doors where they would be fully exposed to prevailing climatic 

 conditions: others were placed in the shelter of buildings or under 

 similar conditions where the favorable nature of the shelter provided 

 might be determined. 



a Boletffl de La Comisida de Parasitologia A^nVola, vol. 2, No. 2, pp. t."> to 61. 



90317— Bull. 77—09 3 



