CHIGGERS — FARRELL 177 



lateral corners extended slightly anteriorly and a median con- 

 vexity adjacent to the anteromedian seta. Lateral margins con- 

 cave, diverging posteriorly. Posterior margin with a slight 

 concavity just medial to each posterolateral corner and broadly 

 convex posteriorly. Anterolateral setae and posterolateral setae 

 on the extensions at the corners; anteromedian seta close to the 

 anterior margin. Setae rather heavy. Pseudostigmata moderately 

 separated, considerably posterior to a line drawn between the 

 posterolaterals. Sensillae clavate; pedicel distinct; expanded por- 

 tion pyrif orm ; setules on anterior surface of head smoother, those 

 on posterior surface fev/er and more offstanding. Anterior to 

 each pseudostigma a long crescentic ridge. Punctae rather widely 

 spaced. Two larger pits or pores about halfway between the pos- 

 terolateral and the pseudostigma visible on one side. 



Standard data of the single specimen studied from Antonito, 

 Colo. : 



Eyes: Two pairs lateral to the posterolateral corners. Diam- 

 eter of anterior eyes, 12 ; of posteriors, 11. 



Dorsal setae: Rather heavy; well clothed with rather short 

 setules; the same form throughout; numerous; tend to occur in 

 bands rather than in rows. Length of a humeral, 57; of a seta 

 from the middle of the first posthumeral row, 54 ; of one from the 

 posterior group, 36. 



Dorsal formula of the single specimen from Antonito, Colo.: 



2 . . 12 . . 12 . . +26 . . +27 . . +15 . . +14 



Ventral setae : Form similar to that of the dorsals. Number of 

 first sternals, 2 ; of second sternals, 2 ; of poststernals, about 100. 

 Length of a first sternal, 54; of a second sternal, 44; of a seta 

 near the middle of the first poststernal row, 32; of a seta from 

 the posterior group, 38. 



Material: Borrowed from the Rocky Mountain Laboratory. 

 Specimen from host: 

 Ochotona sp. 



Antonito, Colo., Sept. 9, 1931, 1. 



Diagnosis: E. guntheri is the only species in the genus which 

 characteristically has two setae on coxa III. 



14. Euschdngastia criceticola Brennan 



Figure 7,6; Plates 7, 15 



Euschdngastia criceticola Brennan, 1948, pp. 465, 473-474, 476, 477, figs. 6, 

 13. 



