Injurious to Man. 



29 



pincers, both ringers being well developed and armed with teeth. 

 In the genus Liponyssus, most of the species of which are parasitic 

 on small mammals, and a few on birds and reptiles, the fingers 

 are usually devoid of teeth, and they have become attenuated and 

 sharply pointed, being much more suitable for cutting through the 

 skin of the host. The species of Dermanyssus are few in number, 

 and are parasitic on birds and mammals ; in this genus the 

 mandibles are still further transformed, the two fingers being 

 fused together to form a very long fine style for piercing the skin. 

 Some of the Gamasid mites belonging to the genera Der- 

 manyssus and Liponyssus occasionally become temporary parasites 



£ * 



Fig. 12. 



Dermanyssus gallinae, Eedi. Parasitic on poultry, cage 

 birds, etc., and sometimes attacking human beings. 

 Female, much enlarged. (After Berlese.) 



of man. The well-known red mite of birds (Dermanysstis gallinae, 

 Redi), which is nocturnal, sucking the blood of fowls, cage-birds, 

 swallows, and other birds, is perhaps the principal offender, some- 

 times attacking persons looking after poultry, and others, and 

 may set up strong pruritus by its bites. 



Dermanyssus hirundinis, which is also accused of attacking 

 human beings, is at most only a variety of D. gallinae. 



Three species of Dermanyssus occur on the rodents found in 

 human habitations in Egypt, and one of them (D. muris, Hirst), 



