LICE WHICH AFFECT DOMESTIC ANIMALS 339 



that will not cause a slight degree of scurfiness on the cows at times. If 

 one will look at a condition of scurfiness carefully he will find that loose 

 portions of the epidermis have lifted, and fragments are thick in the 

 hairs, yet there is no irritation or reddening of the tissues and hence no 

 real injury. Scurfiness is a condition that may occur without an}"- appli- 

 cation to the skin and it should not deter the dairyman from using a con- 

 trol measure that does not cause a real injury. Scurfiness passes in a 

 short time and leaves the skin clean underneath. 



Part 2. Lice Affecting Chickens, Hogs, Goats, Sheep, Horses, and 



Other Animals 



F. C. BisJwpp 



The habits and control of lice on cattle have been discussed in another 

 lecture. Owing to the marked economic importance of lice on other 

 animals, the diversity of their habits and the great difference in the 

 methods of handling the hosts, an additional lecture is devoted to the 

 subject. 



LICE INFESTING DOMESTIC FOWLS 



Fowls are infested with biting lice (order Mallophaga) only. There 

 are a large number of species living on the various domestic fowls. The 

 chicken is infested with about ten species (seven of these commonly), the 

 turkey with four, the pigeon with eight (three commonly), the duck five, 

 the goose seven, the guinea fowl six, and the peafowl four. 



Of course in listing the number of lice on the different hosts enumer- 

 ated there is some duplication. We find that under certain conditions 

 chicken lice are to be found on several of the other domestic fowls and 

 this is true to some extent with forms which are found on other species. 

 There are a number of factors which influence the transference of any 

 of these parasites from their normal hosts. Ordinarily most of them 

 are quite closely restricted to one species of fowl and the habits of the 

 louse and the host are so interrelated that it is doubtful if many of 

 them will continue to breed successfully on strange hosts, although of 

 course they may be harbored for a time. When several species of fowls 

 are closely associated, especially on roosts, there is a considerable chance 

 for the interchange of the different species of parasites and we can not 

 alwa^'s say that when a given species is found on an unusual host it 

 will succeed in establishing itself and breeding thereon. Furthermore we 

 have observed that the young of a species seems to be attacked by a 

 smaller number of species than the adult fowls. In fact some of the 

 species of lice most commonly found on adults do not seem capable of 



