THE 



AMERICAN NATURALIST 



Vol. XLVIII May, 19U No. 569 



ECTOPARASITES OF MAMMALS 



PROFESSOR VERNON LYMAN KELLOGG 

 Stanford University, California 



The wingless permanent ectoparasites of mammals 

 are chiefly of two groups, namely, the Mallophaga, or 

 biting lice, which feed on the hair and dermal scales, and 

 the Anoplnra, or sucking lice, which feed on the blood. 

 Certain mites and ticks, a few of the Pupipara (degener- 

 ate flies) and almost all of the fleas are also ectoparasites 

 of the mammals, but the fleas, numerous and economically 

 important as they may be, are not permanent parasites, 

 for they live as larvaB not on the host of the adult, but in 

 cracks and crevices in floors, or in the soil and elsewhere 

 that the organic detritus used by them as food may be 

 found. The adults, too, hop on and off their host, and 

 often change from one host individual to another, and 

 even from one host species to another. So that the prob- 

 lems of distribution and species-forming with which I 

 am particularly concerned in my studies of the ecto- 

 parasites are not at all the same in such impermanent 

 form as the fleas as in those truly permanent forms, the 

 Mallophaga and Anoplura. 



In these latter there occurs an extraordinary limitation 

 of the parasite individuals and their immediate progeny 

 and future generations to specific and even individual hosts 

 (and their progeny and future generations), so that the 

 Mallophagan and Anopluran fauna of any mammal usually 

 represents a closely inbred family strain biologically iso- 



