146 INSECTS OF ECONOMIC IMPORTANCE 



to the same order as the i^'ad-flies and the common 

 housefly; it is thus not a true tick; ver}^ common on 

 sheep, but seldom causes serious injury to old sheep; 

 lambs are often worried and hindered from ac- 

 quiring fat; the "ticks" cling very tenaciously to 

 the skin and suck the blood; the eggs are hatched 

 within the body of the flies, and the maggot is 

 nourished there until it is nearly full-grown, and 

 is not born until it is nearly ready to change to a 

 pupa ; it is stuck to the fibers of wool ; each fly pro- 

 duces from two to fifteen of these brown puparia, 

 one-third as large as the mother fly; they are laid 

 in the wool to which they adhere, and they give out 

 the adult fly in about three weeks; the "ticks" are 

 most numerous in the spring, cause much irritation, 

 and hinder young lambs from making their normal 

 growth ; their whole life is spent on the sheep. 



Control — Keep the pen clean; after shearing, 

 apply any of the standard "dips" or kerosene emul- 

 sions. 

 The sheep louse (Trichodccfcs sphccrocepliahis) 



A biting louse that works at the base of the wool ; 

 not often abundant. 



CATTLE PESTS 



The OX w^arble, or botfly ^ (Hypodenna lincata) 

 Order — Diptera. Manual, p. 478 



The ox botfly is widely distributed in this coun- 

 try and Europe; it is found on the buiTalo (Bison) 

 here; it causes much loss by afi^ecting the general 

 health of animals and also by its perforations of 

 hides, thus lowering their value ; there is a second 

 species in this country, the European botfly {Hypo- 

 derma hovis) which is very similar in appearance 

 and habits. 



4 Hadwen — Canad. Dept. Agr., Sc. Ser., Bull. 21. 

 Hadwen and Bruce — Canad. Dept. Agr., Sc. Sen, Bull. 22, 



