THAXTEK. — UICKIA AND TRENOMYCES. 377 



the cells above the second or third curved inward in a somewhat 

 crest-like series which lies parallel to the median series and the inner 

 margin of the perithecium, the terminal cell of the series small, 

 triangular, bearing the large basal cell of the primary appendage which, 

 with the small subtending cell, forms a free straight projection, its 

 axis bent inward at an angle of about 45° to that of the receptacle: 

 median series consisting of eight to ten cells, the two or three lowest 

 enclosed by the marginal series, the rest lying against the strongly 

 convex inner margin of the perithecium, the free slightly convex 

 margin of the uppermost reaching almost to the base of the free tip. 

 Perithecium rather stout, its outer margin nearly straight, its inner 

 convex, the outcurved tip, and externally a small portion of the body, 

 free; the apex flat, protruding slightly externally. Spores 28 X 3 m, 

 in perithecium. Perithecium 40-46 X 16-20 //. Basal cell, including 

 foot, 28-33 X 9-11 ju- Total length, not including primary ap- 

 pendage base, 12-16 X 6-8 n. Appendages 6 X 2 ^ or smaller, 

 wholly smoky brown, usually broken off, the dark base not conspicu- 

 ous. 



On legs of Celaenopsis sp. No. 2229, Amazon, "M. & M." 

 (Mann No. 41). 



A very well marked species peculiar for its more or less regularly 

 spathulate outline, which is broken only by the projecting tip of the 

 perithecium and the primary appendage. It is not nearly allied to 

 other known acarine species, but is perhaps most nearly related to 

 R. minuta. 



Rickia excavata nov. sp. 



General form roughly triangular, distally concave. Basal cell 

 three or four times as long as broad, its distal fourth included in the 

 angle between the two lower cells of the marginal series. Anterior 

 series consisting of four cells, the lower three subequal, usually all 

 appendiculate, the uppermost vertically elongated, externally convex, 

 extending to the middle of the venter of the perithecium: posterior 

 series consisting of usually seven cells, the four lower similar to those 

 of the anterior series, usually all appendiculate, the subtending cells 

 hardly intruded between adjacent members of the series, the three 

 terminal cells successively smaller, flattened, their septa at right 

 angles to the axis of the series which they form, and which is continu- 

 ous with that of the primary appendage and its basal and subtending 

 cells, which, together with the two terminal cells of the posterior 

 series form a free subtriangular projection directed at an angle of 



