ART. 13, DERMANYSSID MITES OF NORTH AMERICA—-EWING, 13 
Type locality.—Species originally described from specimens obtained 
in London zoological gardens. 
Type.z~—The location of the type is unknown to the author. 
This description based on three females, one from snake, Atlanta, 
Georgia; and two from snake, New York City. Collector (?) Clif- 
ford Pope. 
Genus ICHORONYSSUS Kolenati. 
KEY TO NORTH AMERICAN SPECIES, 
a', Dorsal shield about as broad as long................-. I. semitectus (L. Koch). 
a’, Dorsal plate scarcely half as broad as long. 
b'. Dorsal shield of female with lateral margins concave. 
c', Sternal plate of female about two-thirds as long as broad and posterior mar- 
gin but slightly arched; coxae without posterior spines. 
I. sternalis, new species. 
c?. Sternal plate of female scarcely one-half as long as broad; coxae II, ILI, and 
IV with large posterior spines...............-... I. carnifex (C. L. Koch). 
b*. Dorsal shield of female with lateral margins decidedly convex. 
I. isabellinus (Oudemans), 
ICHORONYSSUS SEMITECTUS (L. Koch). 
Trigairdh in his Monographie der arktischen Acariden gives a 
record of this species from Greenland. A brief diagnosis of the 
female is here given, data being obtained chiefly from Trigardh’s 
figures. 
Female.—Dorsal shield covering the cephalothorax completely for 
most of its length and reaching somewhat beyond the middle of the 
abdomen; it is almost as broad as long. Peritreme curved but not 
sinuous and reaching to about the anterior margin of front coxae. 
Sternal plate about as broad as long and broadly excavated on the 
sides near the second coxae. Anal plate somewhat triangular; anus 
in front of middle transverse line; anal or paired setae small; median 
setae a long spine reaching for half its length beyond the tip of 
abdomen. 
Greenland specimens from Myodes torquatus. Other records for 
this species come from Siberia and Novaja Zemlya. 
ICHORONYSSUS STERNALIS, new species, 
Female.—Mounted specimen red (probably due to engorgement). 
Dorsal shield entire and covering most of the body, evenly rounded 
behind. Peritreme sinuous and extending well in front of the second 
coxae. Sternal plate broader than long and barely reaching the third 
coxae; sternal setae subequal; anterior pair situated just behind the 
anterior margin; middle pair situated inside lateral margins and in a 
direct line between the anterior and posterior setae; posterior setae 
situated at the middle of angular processes. Anal plate broady] 
rounded in front and pointed behind; anus slightly oval in outline 
60466—23—Proc.N.M.vol.62——34 
