220 BRITISH TYROGLYPHID^E. 



at the base of Arthropod hairs; it also differs in having 

 only two pairs on the hind margin instead of the four 

 pairs near to it in the male ; it is also rather less 

 diamond-shaped. 



Nymph and Larva. Kramer found these, but has 

 not described or figured them; they are both practically 

 colourless, and do not show the accumulations of white 

 excretory matter beneath the cuticle which are con- 

 spicuous in the adults. The legs are quite trans- 

 parent. 



The nymph more resembles the male than the 

 female in shape; the hairs on the notogaster are 

 raised on papillae as in the male; the papillae are trans- 

 parent, not chitinized, and some of them are rather 

 large ; the hairs themselves, however, are more like 

 those of the female, but are not quite so long in 

 proportion to the body ; they are flexible, but not 

 highly so. Epimera of the first pair of legs joined to 

 a very short sternum, the others free. 



The larva is more parallel-sided than the nymph, 

 and its notogastral and peripheral hairs are shorter ; 

 otherwise they resemble those of the nymph. The 

 two epimera of the first pair of legs join in the median 

 line, but there is not any sternum. There is a con- 

 spicuous chitinous disc (or ring) on each side of the 

 body between the first and second legs. 



Egg elliptical, yellowish white, with several longi- 

 tudinal, undulated, brown, chitinous ridges on its 

 outer surface. 



Hypopus (fig. 6). Light yellowish brown; 

 polished ; an unequal diamond shape. The abdomen 

 much longer than the cephalothorax, only slightly 

 rounded posteriorly. Above the rostrum is a curious 

 hood of clear chitin (PL III, fig. 18), which projects 

 nearly from the level of the dorsum of the cephalo- 

 thorax, and is immoveably fixed to it, but is divided 

 from it by a distinct line when seen from above ; this 

 hood has a cheek-like, rounded lamina of rather darker 

 chitin on each side, which falls almost perpendicularly 



