16 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 62. 
Type locality.— Holland. 
Type.—The location of the type is unknown to the author. 
North American records as follows: From mouse, Washington, 
District of Columbia; from mole, Corvallis, Oregon, June 3, 1912, 
by the writer. Exotic hosts of this species: Putorius, Paludicola, 
and Mus. 
Genus LEIOGNATHUS Canestrini. 
KEY TO NORTH AMERICAN SPECIES. 
a', Dorsal shield of female about as broad near the middle of the abdomen as at the 
shoulders; anal plate somewhat triangular, with pointed caudal area. 
L. crosbyi (Ewing). 
a. Dorsal shield of female only about one-half as broad near the middle of abdomen 
as at shoulders; anal plate of female not at all triangular and with caudal 
area broadly rounded behind................... L. constrictus, new species. 
LEIOGNATHUS CROSBYI (Ewing). 
Female—Stout, with body clothed above with short setae. Palpi 
long, reaching to about the middle of anterior tibiae. Dorsal shield 
about as broad near the middle of the abdomen as at the shoulders 
and broadly rounded behind. Peritreme quite sinuous and extending 
to the front margin of anterior coxae. Sternal plate slightly broader 
than long; reaching the third coxae and anterior corners produced 
into cusps; anterior setae situated just behind the anterior margin; 
middle setae situated away from lateral margins but outside a line 
from anterior to posterior seta; posterior setae situated nearer lateral 
than posterior margin; all sternal setae long, slender, and subequal. 
Anal plate with broadly rounded anterior margin and almost straight 
sides; anus with longitudinal diameter greater than transverse; anal 
area minute; setae of anal plate about straight and subequal. Legs 
short and stout. Length, 0.60 mm.; width, 0.38 mm. 
Male.—Unknown. 
Type locality—Rockport, Missouri. 
Type.—Type (holotype) established at time of original description, 
and at present in the writer’s collection. A single record from a bat 
(Vesper subulatus), type locality, by C. R. Crosby. 
LEIOGNATHUS CONSTRICTUS, new species. 
Female.—Stout, with the body constriction rather pronounced. 
Palpi long, reaching to the tibia. Dorsal plate only about one-half 
as broad near the middle of abdomen as at shoulders. Peritreme very 
sinuous and extending to opposite the anterior coxae. Sternal plate 
about as broad as long. Anal plate twice as long as broad; anus 
with longitudinal diameter greater than transverse, its rim poorly 
chitinized and very thin behind; paired setae situated about halfway 
