CHAPTER V 



INSECTS PARASITIC ON DOMESTIC ANIMALS AND 



MAN 



Domesticated animals are those whose ancestors were once 

 wild, but which have been tamed because of their usefulness to 



man. Insects may affect domestic 

 animals in a number of different 

 ways; first, by occasional attack 

 for the purpose of obtaining food; 

 second, by occasional attacks which 

 simply give irritation to the ani- 

 mal, as in the case of certain species 

 of flies; third, by living as parasites 

 during part of their existence, as 

 in bots; fourth, by living as para- 

 sites throughout their lifetime, as 

 with the lice ; and, fifth, by living 

 as messmates or scavengers upon 

 the bodies of the animals without 

 deriving nutriment from them, as, 

 probably, some species of bird lice. 1 

 Practically all of these insects are 

 parasites and are modified in struc- 

 ture and habits because of their 

 parasitic methods of life. Of the 

 hundreds of different kinds of in- 

 sect parasites the four most important groups are the botflies, 

 fleas, lice, and ticks. Man, as well as the lower animals, is 

 attacked by them. 



1 Osborn, H., Insects Affecting Domestic Animals. 

 48 



Fig. 28. — Horse botfly : A, 

 egg attached to hair ; B, larva 

 showing spines ; C, adult female. 

 (After Osborn.) 



