DISCUSSION OF GENERA AND SPECIES 41 



more or less misshapen and with the tarsus much reduced, the latter (Fig. 

 17 A) well formed and large, 6-segmented, with the third segment very 

 long. Stigmatic depressions not indicated, the stigmatic spines lacking. 

 Marginal spines lacking except along the margins of the anal cleft (Fig. 

 17 D], where there are numerous slender setae. Anal ring practically 

 simple, bearing six short setae. Dorsum beset with small, circular pores 

 with a chitinized rim (Fig. 17E), which are especially numerous over the 

 posterior half. In fully mature individuals the derm becomes extremely 

 heavily chitinized, and it is practically impossible to obtain preparations in 

 which these various structures can be seen. 



Second stage with the antennae practically as in the adult but slightly 

 more slender. Legs well formed, large and slender. Marginal spines 

 (Fig. 17F) quite large, slender, conical, set in a sharply defined single 

 row, the spines being separated from each other by a distance of scarcely 

 more than the width of their bases. Stigmatic depressions scarcely no- 

 ticeable, the stigmatic spines but little or not at all larger than the other 

 marginal spines. Anal plates (Fig. 17 C] rather slender, each with three 

 apical spines and a single spine on the mesal margin and a single sub- 

 apical spine on the ventral side. There are four very small fringe setae. 



First stage not seen. 



Physokermes taxifoliae Coleman. 



Originally described from this area, where it occurs rather sparingly 

 on the Douglas spruce, Pseudotsuga taxlfolia. I have been unable to ob- 

 tain suitable specimens for microscopic examination. 



Genus TOUMEYELLA Ckll. 



Toumeyella pinicola n. sp. 

 Fig. 18. 



Type host and locality. From Pinus radiata on the grounds of the 

 Spring Valley Water Company at Aqua, San Mateo County, Calif. 



Habit. Occurring on the small twigs at the bases of the needles. 

 Entirely destitute of secretion ; dried specimens much wrinkled, more or 

 less irregular in form because of crowding, somewhat straw colored ex- 

 cept for a small brown area about the anal plates. Length about 3 mm. 



Morphological characteristics. Derm entirely membranous except 

 for a heavily chitinized, circular area about the anal plates. Marginal 

 spines very few, small and slender. Stigmatic spines (Fig. 18E) short 

 and stout, somewhat spindle shaped, the middle spine not longer than the 

 others. Stigmatic depressions shallow, marked by a broad zone of cir- 

 cular pores. which extends in to the corresponding spiracle. Anal plates 

 (Fig. 185) large, the cephalic margin distinctly longer than the caudal 



