30 Transactions of the Society. 



indentatiou. The vulva of parturition is placed between the third 

 and fourth pairs of legs; it consists of two somewhat chitinized 

 labk, protected on each side by a band-like sclerite, and anteriorly 

 by a horseshoe-shaj^ed sclerite ; there are a pair of suckers concealed 

 beneath each labia. The hind margin has three pairs of hairs, at 

 difierent levels. 



The female is far less active than the male. 



Nym2)h. 



This when fully grown, except in the absence of external repro- 

 ductive organs, so closely resembles the female that it is scarcely 

 worth describing it separately. 



Hypopial Nymj^h. 



Proportion of length to width about 13 to 6. 



This curious stage is chiefly remarkable amongst Hypopi for the 

 conspicuous eye, or eye-like organ, which is found on each side of 

 the anterior edge of the cephalothorax. 



Colour, light chitinous brown. 



Texture hard and polished, the notogaster almost transparent. 

 A largo number of round free cells, quite irregularly placed, lie 

 immediately beneath the chitin, and give the creature a dotted 

 appearance. 



Cephalothorax. Covered with a semi-transparent carapace, 

 from beneath which the point of the rostrum slightly projects. 

 The mouth-organs are the usual two papillae, each terminating in a 

 bristle. There are not any markings on the cephalothorax, but a 

 very large, simple eye, or eye-like organ, is situated on each side of 

 the rostrum, on the anterior edge of the body, and just above the 

 first leg. This organ is half beneath the carapace and half 

 projecting beyond it ; the side beneath the carapace (the inner side) 

 is coated internally with a conspicuous layer of black pigment, 

 while the portion projecting has the appearance of a lens. 



The legs are long and robust for a Hyjwjms ; the two anterior 

 pairs projecting clear of the body almost the whole length of the 

 lour anterior joints ; the hind legs also project substantially. All 

 the legs are terminated by a single claw without sucker or caruncle. 

 The hind legs do not terminate in hairs, as is so frequently the 

 case ; but each leg of the two hind pairs has an extremely long, 

 flexible hair springing irom the upper side of the tarsus ; these 

 joints are clothed with the usual fine hairs, and there are a few fine 

 hairs on the other joints. 



Abdomen considerably arched, anterior margin rounded, 

 posterior margin with a slight tendency to be pointed ; it is almost 



