84 



Kecorded from rats from Europe and Africa. 

 Lselaps stabularis Koch. 



The body is of the same general shape as in L. echidninus, but the 

 dorsum is clothed with 12 to 18 rows of fine short hairs. The first 

 pair of legs is more slender than in the other species, and the hind 

 legs are also more elongate; the coxae do not have the stout spines 

 seen in the other species, and the bristles on the sternal and ventral 

 plates are much less stout; the general surface of the venter has 

 many hairs, the anal plate has a short apical bristle. Length, 

 1.2 millimeters. 



Taken on the brown rat in Italy; also found in manure. 



CHEYLETID^E. 



This family consists of small, soft-bodied mites, that are parasitic 

 or predaceous in habits. The palpi are small, three or four jointed; 

 the mandibles are styliform and retractile; and the breathing spira- 

 cles open near the mouth parts. The species that occur on rats 

 belong to the genus Myobia. 



Myobia. The body is elongate, fully twice as long as broad, tipped 

 by a pair of long, stout bristles. The first pair of legs is enlarged and 

 shortened, with a terminal hook to grasp hairs; the other legs are 

 short, simple, and far apart. The palpi and mouth parts are very 

 small, and the dorsum bears stout bristles. They are supposed to 

 feed on the exudations of the skin, but it would seem more probable, 

 from the nature of the mandibles, that they pierced the skin to secure 

 food. All are very small, not one-half a millimeter long. Of the 

 several species two have been recorded from rats. 



1. Dorsum of female with spines all acute and sharp M. musculi. 



Dorsum of female with some of the posterior spines flattened and rather scale 

 like M. ensifera. 



Myobia musculi Schrank. 



This occurs on various mice and moles, and once recorded from the 

 brown rat. It has been taken in this country on mice. It lives at 

 the base of the hairs. 

 Myobia ensifera Poppe. 



This was described from the brown rat in Europe. The female is 

 separated from M. musculi by having about six of the posterior dor- 

 sal spines flattened and scale like; in the male the six dorsal spines 

 are longer, and the small spines much smaller than in M. musculi. 



SARCOPTID^. 



These are the itch and scab mites. The body is soft, rounded, and 

 whitish in color. The legs are very short, of five joints, and end in 

 one or two claws, and often a pediceled sucker. The palpi are small 



