204 PROCEEDINGS OF THE NATIONAL MUSEUM vOL. 106 



Geographic distribution: E. cmteris has been collected in 

 Pennsylvania from the northwestern, the central, and the north- 

 eastern parts of the State (fig. 7,c). 



Diagnosis: E. crateris can be distinguished from the other 

 members of tlie "blarbiae" group by the shape of its galeal setae, 

 by the long spur on the palpal tarsus, and by the large number 

 of dorsal setae. 



Ecology: Concerning the collection of June 26 or 27, 1949, 

 Mr. C. L. Gifford noted: "These were taken on hot, dry cliffs of 

 limestone and dolomite. A number of Peromyscus \\Tre taken 

 there and they were almost 100% infested with that type of 

 chigger." Unpreserved ears of this collection were received in 

 the laboratory. The ears and the chiggers were dessicated. The 

 chiggers were found in pits, particularly along the edge of the 

 pinna. 



Remarks: E. crateris has been named for the pits or craters 

 in which it was found on the ears of Peromysciis. 



23. Euschongastia setosa (Ewing) 



Figure 8,o; Plates 8, 18 



Tromhicula setosa Ewing, 1937, pp. 170-171.— Radford, 1942, p. 60.— 



Michcner, 1946, p. 432.— Sig Tlior and Wilimann. 1947, pp. 258, 273. 

 Euschongastia setosa, Fuller, 1948, pp. 103, 104; 1952, p. 184. 



Description : Size : Length, 205 to 635 ; width, 150 to 590. 



Shape : Unattached in life, ovoid, idiosoma rounded. Preserved, 

 broad ovoid to broad oval. 



Color : Yellowish with red eyes. 



Gnathosoma: Seta on palpal femur well covered with setules 

 on outer curvature. Seta on palpal genu with a few long setules, 

 often in two rows. Dorsal seta on palpal tibia with a few alter- 

 nate setules; lateral seta nude; ventral seta with a few slender 

 setules on the dorsal half of the shaft. Palpal claw curved, with 

 five to seven prongs. Galeal seta with about two to six setules; 

 form variable, branched, pectinate, or with setules arising from 

 opposite sides of the shaft; an occasional seta resembling those 

 of E. crateris. Cheliceral base angulate laterally; blade with a 

 very tiny dorsal tooth and a small ventral tooth. Punctae on pal- 

 pal coxa; tiny punctae on cheliceral base, not always discernible. 



Legs: Leg I with two slender genualae and a microgenuala, 

 two tibialae and a microtibiala, a short spur on the proximal half 

 of the tarsus with a rnicrospur about two-thirds the length of the 

 spur distal and slightly posterior, a subterminala, a parasubter- 

 minala, and a pretarsala. liCg II with a genuala, two tibialae, a 

 middorsal spur of moderate length with a rnicrospur proximal 



