NOTHRUS TARDUS. 527 



all over; reticulations about 300 to 350 to the milli- 

 metre, pits about half as wide again as the ridges. 



Cephalothorax of moderate length, narrower, but 

 not conspicuously narrower than the abdomen. Ros- 

 trum rather broad, rounded. Rostral hairs rather 

 long and far apart. No exterior pseudo-stigmata of 

 the ordinary tubular projecting type are visible^ there 

 is, however, undoubtedly a long setiform hair on each 

 side ; it is very doubtful whether this is to be regarded 

 as the homologue of the pseudo-stigmatic organ or of 

 the interlamellar hair ; the position favours the former, 

 the structure, the latter view. A precisely similar 

 arrangement is found in N. mo7iodactylus, and N. glaber ; 

 the last-named species appears to be aquatic, and the 

 other appears also to be sometimes found in sphagnum ; 

 it is worth remembering that the external pseudo- 

 stigmata and pseudo-stigmatic organs are sometimes 

 absent, or beyond my power to detect, in aquatic or 

 amphibious species. The apodemata are joined to the 

 sternum, except the third, in which case those from 

 the two sides join, the sternum ceasing in that part of 

 the body and commencing again further back. 



Legs short, rather thick ; the first pair passing the 

 tip of the rostrum ; the fourth pair reaching to about 

 the middle of the anal plates. The third and fourth 

 pairs are set under the abdomen, but not so much so 

 as in N. monodactylus. The tibise are not longer than 

 the genuals ; tarsi the longest joints; they bear some 

 thick, not very long, setiform hairs in the upper median 

 line, varying in number on the different legs, and there 

 are a few hairs of the same class on almost every joint ; 

 but the thick, tooth-like spikes of the tarsus of N. 

 monodactylus are not found. Glaivs tridactyle ; central 

 claw the shortest. 



Abdomen flat in general level ; shield- shaped^ pro- 

 gaster nearly straight, hut the antero-lateral corners of 

 the abdomen form small rounded projections directed for- 

 wards ; each bearing a large setiform hair directed 

 outward ; hind margin nearly pointed. The central 



