252 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



to determine, its setae and pores are as in adults ; many setae of dorsal 

 and ventral integument barbed ; peritreme not well chitinized. 



Remarks. — Distinctive characteristics that make it possible to dis- 

 tinguish female, male, and nymph of E. harberi from those of other 

 species are: Female: Usual apical setae largest on dorsal shield; 

 many dorsal setae barbed ; six pairs of dorsal pores ; anterior pair of 

 sternal setae barbed ; anterior pair of sternal pores angled posteriorly ; 

 genito ventral shield widely expanded posteriorly ; with over 100 acces- 

 sory setae; anal shield with three usual anal setae and five smaller 

 accessory setae ; posterior usual anal seta largest on shield and barbed ; 

 about 12 multiple fimbriae on each lateral margin of epistome; each 

 chela with two teeth ; fixed chela with a bifid tip ; all maxillary setae 

 berbed; almost all setae on legs barbed. Male: Setation of dorsal 

 and ventral surfaces as in female; ventral shield widely expanded 

 posterior to coxae IV and curved anteriorly lateral to coxae IV ; anal 

 region distinct; epistome as in female; structure of chelae distinct; 

 all maxillary setae barbed ; maxillary corniculi blunt ; conspicuously 

 stout ventral setae present on leg II as follows : Femur two, genu one, 

 tibia one, tarsus two. Nymph: Setation and mouth parts as in 

 female. 



Ewing (1925) described E. harberi as differing from microti only in 

 having the outline of the epistome oval in barheri and not in microti 

 and the marginal teeth of the epistome large and branched in microti 

 and small and single in barberi. Results of examination of type 

 material and of specimens from a variety of hosts in Maryland indicate 

 that these species are synonymous and that on the basis of page pri- 

 ority barben is the valid specific name. Outline of epistome and 

 number of simple and multiple fimbriae on epistome may vary slightly 

 among individual specimens, but not sufficiently or consistently 

 enough to indicate a species distinction on that basis. 



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

 952/x to 1,092/a; mean was 1,025/x. It was possible to obtain accurate 

 measurements of body width in only 12 specimens ; in these it varied 

 from 588/A to 644/^. Ewing gives the length of one of the type females 

 as 1,050/x ; its width as 720;a. 



Distribution and hosts. — Ewing's type material of barberi was taken 

 on the Maryland shore of the Potomac River near Plummers Island ; 

 type material of microti was from Bronxville, N. Y. Additional speci- 

 mens in the U. S. National Museum collection were taken only from 

 the eastern United States and southeastern Canada. I have examined 

 specimens from the following hosts: PitymAjs 'pinetomim,^ Point 

 Abino, Welland County, Ontario, September 16, 1945. "Pine mouse," 

 Willow Groove, Del., June 23, 1939; Petersburg, Va., April 1933; 



