278 BRITISH TYROGLYPHID^E. 



placed between the coxae of the third and fourth pairs 

 of legs, and is surrounded by a strong, chitinous, 

 elliptical ring, the transverse axis of which is the 

 longer. This ring has a short, blunt, anterior, central 

 projection. Inside the ring are the labia; the two 

 ordinary lateral labia are widely separated posteriorly ; 

 behind them is an unpaired, posterior, almost triangu- 

 lar labium opening downward and backward. The 

 anus is much smaller than the vulva; it is a long- 

 ellipse placed far backward ; there are a pair of short 

 spines behind it. 



Male. The cephalothorax is somewhat shorter and 

 broader in proportion than that of the female; the 

 same observation applies to the mandibles. The 

 abdomen is almost elliptical, but is somewhat prolonged 

 anteriorly; the hind margin is rounded, and entirely 

 devoid of the bilobed shape of the female. The 

 notogaster is without the lobes of the female ; its 

 centre is arched, but not strongly so; the lateral 

 margin is slightly raised, and usually has a few 

 wrinkles in addition to its otherwise rough texture. 

 The legs (PI. XVII, figs. 810) are remarkable, and 

 are very different from those of the female; they are 

 very thick and heavy, much more so than those of the 

 female ; the coxae, tibiae, and genuals are broader than 

 they are long. The most remarkable feature consists 

 in certain projections from the undersides of the first 

 two pairs of legs. From the median line of the under- 

 side of the tibia of each of these legs there projects a 

 flat, fan-shaped blade of clear colourless chitin edged 

 by seven to nine deeply-cut teeth or spikes, radiating 

 outward. On the underside of the femur of the second 

 leg are two blades of similar texture ; the proximal 

 round, with a thickened central boss ; the distal curved, 

 but longer in shape ; both these are edged with radiat- 

 ing spikes similar to those on the tibia. The tarsi of 

 the two anterior pairs of legs have broad curved blades, 

 both above and below, in the median line ; and there is 

 one on the upper side of the tibia of the second leg, 



