CHIGGERS — FARRELL 161 



Color: Yellow (Brennan, 1948). 



Gnathosoma : Seta on palpal femur strong, curved, well covered 

 with strong setules on convex curvature. Genual seta thinner, 

 with a few long, slender setules alternately arranged. Dorsal 

 seta on palpal tibia slender with few, slender, alternate setules; 

 lateral seta slender with one to three slender setules; ventral 

 seta with setules spaced alternately in two dorsal rows. Palpal 

 claw strong, slightly curved, three-pronged, the two smaller ac- 

 cessories arising together on the basal half. Galeal seta rather 

 small with two or three setules. Chelicera typical; base heavy; 

 blade smoothly curved with small subapical dorsal tooth and a 

 larger ventral tooth. Punctae on palpal coxa and cheliceral base. 



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

 two tibialae with a microtibiala, a rather small spur with micro- 

 spur about half the length of the spur distal, a subterminala, a 

 parasubterminala, and a pretarsala. Leg II with a single slender 

 genuala, two shorter tibialae, a rather long, slender spur with 

 microspur near the base, usually anterior, and a pretarsala. Leg 

 III with a slender genuala and a slender tibiala. Nonspecialized 

 setae generally with setules shorter and finer than in E. peromysci. 

 All leg segments punctate. 



Scutum: Shape generally similar to that of E. peromysci but 

 more fully rounded. Setae well covered with short setules, but 

 less densely than in E. peromysci. Pseudostigmata well behind 

 a line between the posterolateral setae, deep and globular. En- 

 larged portion of sensilla ovoid or v/ith tips truncate; well cov- 

 ered with setules on anterior surface, fewer on posterior surface ; 

 pedicel rather long, enlarging into the head. A strong ridge 

 arises anteromedial to each pseudostigma, curving anteriorly, 

 laterally, and posteriorly to the posterior margin of the scutum ; 

 the two ridges sometimes continuous medially. Surface punctate. 

 Cuticular striae apparent over posterior margin. 



Standard data of the five specimens studied from Ravalli 

 County, Mont. : 



AW PW AP SB ASB PSB AL AM PL S 



'Expanded portion only. 



Eyes: Two pairs, anterior pair lateral to posterolateral setae. 

 Diameter of anterior eyes, 10 to 11, mean 10.4; of posterior eyes, 

 9 to 11, mean 10.4. 



