160 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 106 



obtained from forest soil materials through Berlese funnels. These 

 were distributed in seven cells which were then attached to the 

 palmar surfaces of a man's forearms. When the applications 

 were examined 41/2 to 7 hours later, two chiggers were missing 

 from the cells. Of the chiggers found in the cells, nine were dead 

 and four were alive. One of the living chiggers, examined 51/2 

 hours after application, was attached to the skin. It was fastened 

 securely in the center of a small reddish spot about 2 mm, in 

 diameter. Apparently'' it was attached at a pore, not at the base 

 of a hair. When first observed, it was wet with water or per- 

 spiration; all legs projected sharply posteriorly and it did not 

 move. Nudged repeatedly v/ith a dissecting needle, it was thrust 

 about, pivoting on its gnathosoma. In a short tim.e it began to 

 move its legs in the air. Several trials were made with a dissect- 

 ing needle before the chigger was removed from the point of 

 attachment and preserved. All other chiggers also v/ere preserved. 



Remarks : The known range of E. peromysci gives it the widest 

 distribution of any North American Euschongastia. It varies 

 within limits through its range. Certain variations, which have 

 been charted, seem to have geographical continuity. The fre- 

 quency with which it has been collected indicates E. peromysci 

 is the most common Euschongastia to be found on small mammals 

 east of the Mississippi River. 



Examinations of the holotype of E. peromysci (Ewing, 1929) 

 and of the cotypes of E. signator (Ev/ing, 1931) and E. brevipes 

 (Ev/ing, 1931) showed all three species to conform to the same 

 morphological pattern. The ranges of E. peromysci and E. 

 brevipes have been united by subsequent collections. Collections 

 have not yet united this eastern range with that of E. signator, 

 but the nev/er records from Ohio, Kentucky, and North Carolina 

 point toward the continuity. Certain morphological characters 

 of E. signator do appear at the limits of variation of the species, j 

 so that a possibility of subspeciation remains. However, on the ! 

 basis of morphology'' and geographical distribution, the three 

 species are here considered to be the same and E. brevipes and 

 E. signator to be synonyms of E, perowAjsci. 



9. Euschongastia cordiretnus Brennan 



Figure 4,a; Plates 6, 12 



I 

 Euschongastia cordircmus Brennan, 1948, pp. 465, 470, 471, 477, figs. 5,a-d, I 



11. ' 



Description: Size: Length engorged, 410 to 580; width, 225 

 to 350. 



Shape : Long ovoid or oval. 



