276 BRITISH TYEOGLYPHID^l. 



the creature has just emerged from the nymphal skin 

 the hinder part of the abdomen of the female is lighter 

 than the anterior portion ; at this time, in both sexes, 

 there is a pinkish shade, and the tint, of course, is 

 lighter. 



Texture. Dull and rough, rather granular, the 

 female more strongly so than the male. 



Female, Cephalo thorax, as seen from above, about 

 one-fifth of the total length ; narrow ; lateral margin 

 (behind the rostrum) concave ; the posterior part of 

 the cephalothorax is as wide as the anterior margin of 

 the abdomen, or nearly so. Rostrum somewhat trun- 

 cated or concave anteriorly. Rostral hairs very short. 

 A narrow, raised, longitudinal ridge starts from near 

 the rostral hair on each side ; after following the line 

 of the rostrum for a short distance it curves toward 

 the median line ; after the middle of the cephalothorax 

 it curves outward again, and runs as far as the anterior 

 margin of the abdomen. Mandibles (PI. XVI, fig. 6) 

 short, powerful; tridentate on each limb of the chela. 

 The mandibles, when not in use, do not usually project 

 beyond the rostrum. There is a strongly chitinized 

 concavity on each side of the cephalothorax near the 

 base, which holds air when the creature is immersed in 

 liquid. It appears to be partly closed by a membrane, 

 and to have a nerve running to it. Possibly it may be 

 a sense-organ, and if so, is probably auditory. It is 

 found in both sexes. The abdomen is a long heart- 

 shape with the point placed anteriorly, and the two 

 rounded lobes forming the hind margin ; between them, 

 on the dorsal level, is the small tubular projecting 

 bursa copulatrix. The lobes are considerably raised 

 and rounded on the dorsal surface ; they occupy the 

 whole central part of nearly half the abdomen ; anterior 

 to them is a single broad lobe, less raised, occupying 

 the central part of the greater portion of the remainder 

 of the abdomen ; it bears two longitudinal irregular 

 ridges on its dorsal surface near the median line, and 

 there is a depressed trench along the lateral border of 



