234 STANLEY HIRST ON 



Locality : Museiom Menagerie, Paris (on a Buffalo from Cochin China). 

 Ovigerous Pubescent 



female. nymph. Male. 



Length . . — 450/^ 480-510/* 



Width . . — 312 Ai 332-340 m 



Psoroptes communis Fiirstenberg.^ 

 I have examined a large series of specimens of Psoroptes 

 from various domestic animals and can find very little structural 

 difference between them. It seems certain that the mites of this 

 genus (with the exception of Psoroptes natalensis) must be regarded 

 merely as races or slight varieties of a single species. 



The same appears to be the case in the genus Sarcoptes, for 

 I have examined specimens from a number of hosts, viz. man, 

 dog, fox, rabbit, guinea-pig, pig, goat, cattle, hartebeest, kudu, 

 coatimundi (South American carnivore) and lion, without being 

 able to discover a single constant structural character by which 

 they can be separated from one another. There seems, indeed, 

 to be only a single species in the genus Sarcoptes. 



Although differing so little in structure, various observers 

 have pointed out that it is very difl&cult to transmit mites of 

 the genus Psoroptes from one host to another of a different species. 

 For instance, Delafond and Bourguignon failed to transmit 

 Psoroptes communis var. ovis to any other host. 



The hairs on the abdominal lobes of the male (fig. 3) are all normal 

 in appearance in P. communis, none of them being in the least 

 flattened or blade-like. Two of the hairs (the third and fourth 

 from the outer side of the lobe) are always much longer than the 

 others. In specimens from horses the second hair from the 

 outer side of the lobe is usually longer than in the other races or 

 varieties of P. communis. In specimens from cattle this hair is 

 rather long, but not nearly so long as in var. equL In the variety 

 cervinae (from the Bighorn ; H. B. Ward's coll.) it is variable 

 in length, sometimes being rather long. In the variety cunicuU 

 it is much shorter and finer at the base than in the var. equi. 



1 For the principal literature on this species see Railliet, Traite de 

 Zoologie Medicate et Agricole, 2nd edition, Paris, 1895, p. 666. 



