14 



Farmers' Bulletin 801. 



to a considerable extent, it is not possible to separate them absolutely 

 on this basis. The writers have observed that the relative number of 

 hce of the different species varies much in different flocks in the same 

 neighborhood, and even in the same flock some chickens often have 

 one species predominating, while others have another. Usually 

 three or more species are to be found on an infested fowl. 



THE HEAD LOUSE OP CHICKENS.' 



This species is primarily a head louse, although occasionally found 

 on the neck and elsewhere. It is undoubtedly the most injurious 

 species to young chickens, as many of the other forms wdiich are 

 serious annoyers of grown poultry do not thrive well in the down 

 on chicks. It is a dark grayish species nearly one-tenth of an inch 

 in length, and may be found on the top or back of the head, behind 

 the ears, or beneath the bill. Usually it is lo- 

 cated close to the skin with its head very close 

 to or against the skin of the chicken, the body 

 extending away from the skin on the do^Ti or 

 along the feathers. The eggs are deposited 

 singly on the down or small feathers about the 

 head. Eggs attached to a small feather are 

 shown in figure 7. These hatch in four or five 

 days into minute semi transparent lice which 

 resemble the adult in shape. After molting the 

 skin several times, and in the meantime in- 

 creasing in size and becoming darker in color, the 

 lice reach the adult stage in about 17 to 20 davs. 

 The male of this species is sho^\^l in figure 8. 



Despite the fact that this louse confines its 

 attack principally to the head, it passes readily 

 from one chicken to another and from the 

 mother to her young. This is the species 

 against which the poultry man must guard his 

 young chickens. The treatment recommended 

 for various lice (p. 22) is satisfactory for this 

 species. It is essential that the ai)plications be 

 made to the regions about the head to destroy 

 it on grown fowls, and on young chickens tliis is the only region which 

 requires attention. After young chicks are fairly well feathered the 

 head louse decreases in number, probably because conditions are less 

 favorable for breeding and because the older chickens scratch the 

 infested parts more vigorously. The number of head lice may in- 

 crease again after the chickens become adult. 



Fig. 8.— Uead louse: Male, top 

 view. Greatly enlarged. 

 (Original.) 



THE BODY LOUSE OP CHICKENS. 



The common name ''body louse" is aptly applied to this species, 

 and refers to its habit of remaining on the skin of the fowl rather 



Lipeurua heterographus Nitzsch. 



» Menopon biseriatum Piaget. 



