MITE'S OF SUBFAMILY HAEMOGAMASINAE — KEEGAN 217 



Size. — Thirty-two female specimens examined varied in length from 

 900/x to 1,150/i, and in width from 500/* to GOO^u,; mean length was 

 1,001/i,; mean width 555/*. Three male specimens measured 775/a, 

 Y75/1, and 700/* in length and 425/*, 375/i and 375/x in width. The two 

 measurable nymphs were 525/* and 800/* in length and 350/* and 500/* 

 in width. Ewing's type female measured 1,120/* in length and 700/* 

 in width. 



Remarks. — Distinctive features of Haemogainasy.s alaskensis^ which 

 serve to distinguish female, male, and nymph from those of other 

 species are: Female: Barbed setae on dorsal shield; single pair of 

 accessory setae on anterior margin of sternal shield ; number of sternal 

 setae; number of genitoventral setae; shape of peritreme; shape of 

 epistome, and possession of 10 to 12 multiply branched fimbriae on 

 each lateral margin; fixed chela with a bifid tip and two teeth; 

 movable chela with two teeth ; shape of maxillae and smooth anterior 

 maxillary setae; barbed setae on palpi and legs. JVIale: Similarity 

 to female in all except secondary sexual characters; single pair of 

 accessory setae on anterior margin of ventral shield ; shape of chela ; 

 lack of specialized setae on legs. Nymph : General characteristics of 

 female seen in setation and mouth parts. 



Variation in this species is evident in body size, numbers of ac- 

 cessory setae on sternal, genitoventral, and anal shields, and to a slight 

 degree in the shapes of these shields. 



Haemogamasus sternaUs Ewing, 1933, was described as differing 

 from alashensis only in having the sternal shield poorly sclerotized 

 and festooned behind and in having the sternal setae arranged in 

 irregular, transverse rows. The single female specimen upon which 

 the description was based was taken by Francis Harper, August 12, 

 1925, from a short-tailed shrew, BJarina hrevicauda talpoides., at 

 Adirondack Lodge, Essex County, N. Y. Other than the type the 

 only specimen identified as H. sternalis in the collection of the U. S. 

 National Museum is a female taken from a pine mouse at Chevy 

 Chase, Md. In view of the variation in shape of the sternal shield 

 and in the number and arrangement of accessory setae on it in speci- 

 mens of H. dlaskensis taken from the same and closely related hosts 

 and the same regions, it is my opinion that the two species are synony- 

 mous and that H. alashensis Ewing, 1925, is the valid specific name. 



Distribution. — H. alashensis has been taken most frequently from 

 the northeastern and northwestern United States and southern Can- 

 ada. Records from such widely separated areas as Utah, Illinois, and 

 North Carolina suggest that the more numerous northern records may 

 be due, at least in part, to the presence of more active collectors in those 

 regions. 



