DESCRIPTIONS AND DETERMINATIONS OF SPECIES 25 



Numerous males, females and larvae from Citellus beecheyi douglasi 

 (Cazadero and Palo Alto, Calif.), Citellus beldingi (Tuolumne Meadows, 

 Calif.), Citellus mexicanus (Guanajuato, Mexico), Citellus barrowensis 

 (Pt. Barrow, Alaska), "rock squirrel" (Boulder Canyon, Colo.), Arc- 

 tomys Haviventer (Burns, Oregon), and Citellus columbianus (Pull- 

 man, Wash.) ; the last two records being of specimens taken from skins 

 in the Stanford University collection. Osborn records the species from 

 Citellus columbianus (Pullman, Wash.), and western gray squirrel (Fort 

 Collins, Colo.). 



An examination of Osborn's types of Haematopinus montanus and 

 H. columbianus, together with the study of much other material which 

 we have at hand, has convinced us that these two species really constitute 

 but one species, which should be referred to the recently established genus 

 Lino gnat hoides. The name montanus having been first used, the species 

 becomes Linognathoides montanus (Osborn). 



There is a considerable degree of individual variation among our 

 specimens, particularly as regards size and coloration, some specimens 

 being much larger and more darkly colored than others ; and there is also 

 some variation in the shape of the sternal plate. However, to attempt to 

 distinguish between these forms would require the naming of a variety 

 for every host species. 



Linognathoides inornatus n. sp. 



Plate II, fig. 1 ; plate IV, fig. 7; plate V, fig. -5 ; plate VI, fig. 3 ; text 



fig. 10. 



Two females and three males from three specimens of Neotoma 

 (Teonoma) cinerea occidentalis, bushy-tailed wood-rat (South Yolla 

 Bolly Mt., Tehama county, Calif.). This species differs from L. colum- 

 bianus chiefly in the shape of the sternal plate and in the presence of a 

 pair of finger-like processes at the end of the abdomen of the male. 



Description of the Female. — Total length 1.3 mm., length of head 

 .28 mm., length of abdomen .95 mm., width of head .18 mm., width of 

 thorax .26 mm., width of abdomen .4 mm. 



Head with the anterior margin slightly convex, the lateral margins 

 of the forehead nearly parallel, diverging sharply immediately behind the 

 antennae. Temporal margins nearly straight, converging slightly, the 

 posterior lateral angles sharp. Occiput narrow, with the posterior mar- 

 gin prolonged into a point. A few small spines on the anterior margin, 



