CHIGGERS — FARRELL 183 



five long setules. Palpal claw strong; three-pronged; median 

 prong longest and heaviest ; prongs arise near middle or on distal 

 half. Galeal seta nude or with one, two, or three setules. Chelicera 

 large; distinct subapical dorsal and ventral teeth on blade. Pal- 

 pal coxa and cheliceral base usually without apparent punctae, 

 occasionally with very small, faint punctae. 



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

 two tibialae, the more proximal longer, and a microtibiala, a 

 rather small spur and a distal microspur, a subterminala, a 

 parasubterminala, and a pretarsala. Leg II with two rather small 

 tibialae, a slender spur with proximal microspur, and a pretar- 

 sala. No genuala II. Leg III with no specialized setae. Non- 

 specialized setae with few setules. Empodium long. Usually no 

 punctae apparent, occasionally fine and faint on coxae. 



Anomaly: One specimen with two setae on one coxa III. 



Scutum: Shape somewhat variable, about tv/ice as wide as 

 long. Anterior margin convex between anteromedian seta and 

 the anterolaterals. Lateral margin straight or slightly concave, 

 diverging posteriorly. Posterior margin convex; or convex pos- 

 terior to the pseudostigmata and slightly concave between them; 

 or made up of three rather straight lines joined bj'' short curves 

 near the pseudostigmata. Posterolateral corners somewhat 

 pointed. The five setae set close to margin; setae rather heavy 

 with relatively few setules. Pseudostigmata posterior to a line 

 drawn between the posterolateral setae. Sensilla long clavate, but 

 with distinct pedicel, widest about four-fifths the length from the 

 base ; distal end rounded or slightly pointed ; covered with setules 

 on the anterior surface, setules fewer and shorter on posterior 

 surface. Usually without ridges anterior to pseudostigmata; two 

 specimens with ridges suggested. No punctae apparent. Usually 

 with two or three small pits on each side between the postero- 

 lateral seta and the pseudostigma. 



Summary of standard data of five specimens, three from Ravalli 

 County, Mont., and two from Camas County, Idaho (AM's from 

 four specimens, S's from three) : 



AW 60-70, mean 64.6; PW 84-102, mean 92.2; AP 16-25, mean 20 

 SB 29-42, mean 32.8; ASB 24-33, mean 29.2; PSB 10-13, mean 12 

 AL 39-48, mean 42.8; AM 38-43, mean 39.8; PL 58-62, mean 60.2 

 S 34-44, mean 40. Width of head of sensilla in three specimens, 14, 

 15, and 16. 



Eyes: Two pairs lateral to the posterolateral setae. Diameter 

 of anterior pair, 11 to 13 ; of posterior pair, 9 to 12. 

 Dorsal setae: Rather heavy with relatively few heavy setules. 



