£1 per head of horned cattle. This loss is shown to fall very laro;ely 

 on the cattle owners and also, to a less extent, on the butchers in 

 the depreciation of the value of the carcass. 



These figures seem very large and startling, but the loss is of such a 

 nature and so widely distributed that, until comprehensive statistics 

 like the above are collected, the amount of damage annually suffered 

 is hardl}^ appreciated. The losses are sufficient, at any rate, to indi- 

 cate that the cattle interests have few worse enemies than this bot-fly. 

 Before entering upon the subject of remedies, the habits and life his- 

 tory of the insect will be briefly detailed. 



LIFE HISTORY AND HABITS. 



It was formerly believed that the parent bot-fly deposited its eggs on 

 the backs of cattle, on the hair, or attached them to the skin, and that 



Fig. 3.— Piece of warliled hide — warbles about half size (after Ormcrod). 



the young larvjB on hatching burrowed through the hide and gradually 

 developed until they attained full growth in a cell formed b}^ them in 

 the connective tissue immediately beneath the skin. Dr. Cooper Cur- 

 tice, who has made very careful and interesting studies of the life his- 

 tory of this insect, has shown that an entirely different course is fol- 

 lowed. The facts obtained by Doctor Curtice have been supplemented 

 by investigations, more particularly of the egg-laying habits and first 

 stages of the larvge, conducted through the agency of this Division. 

 Briefly, the life habits of this insect are as follows: 



Very early in the spring, as early as January or February in south- 

 western Texas and later northward, the flies begin to a])pear about 



