80 NEW ZEALAND NEVBOl'TERA. 



the utmost difficulty. In fact, the smaller cases are quite 

 impossible to detect, and this circumstance no doubt 

 often prevents the enclosed larva from being destroyed 

 by the numerous and rapacious enemies, to which a 

 minute marine form must be constantly exposed. As I 

 have found cases of all sizes in considerable numbers both 

 in October and also in January, it may, I think, be fairly 

 assumed that the larvae lives in the sea during the winter 

 months, and in fact throughout the entire year. 



The length of a full-grown larva is about jV inch. The head is rounded, 

 oval in form, blackish with a pale spot on the top ; the prothorax is also 

 black, the meso- and meta-thorax are green with two black, horny, dorsal 

 plates. Both head and thorax are furnished with strong black bristles. 

 The anterior legs are rather short and stout, the two other pairs somewhat 

 long, rather slender. They are furnished with numerous short bristles. 

 There is a pair of respiratory organs on each of the first eight segments of 

 the abdomen. Each gill consists of a bundle of five filaments on a single 

 footstalk. These gills are largest near the thorax, and become smaller 

 towards the posterior extremity of the larva. The abdomen itself is pale 

 green and very soft. There is a small hump on the back of the first segment, 

 and a protuberance on each side ; there are two humps on the back of the 

 second segment. The last segment has two short curved claws, each seated 

 on a moderately large protuberance. The last two segments are also fur- 

 nished with a few strong black bristles. 



When full grown the larva firmly fixes its case to the 

 coralline seaweed, and closes up both ends with a 

 loose network of silk, after which the enclosed insect is 

 transformed into a pupa. This pupa has very strong 

 mandibles, which are no doubt serviceable to the creature 

 when escaping from the case. As is usual with caddises, 

 the pupa swims about for some hours before the final 

 transformation takes place. 



The perfect insect appears about January. It frequents 

 rocks on the sea-beach, and is sometimes extremely 

 abundant. I have met with it in great numbers on the 

 open coast, near the entrance to Wellington Harbour, 

 where I also obtained many of the larvae. Although I 

 made a very careful search amongst the seaweed in rock- 

 pools inside the harbour, I was unable to find a single 

 specimen. I understand from Captain Hutton that the 

 same, or a very similar marine caddis-fly, has been found 

 in Sydney Harbour ; and seeing that the insect is 

 evidently most at home in the open sea, there appears to 

 be no reason why this adventurous little species should 

 not be widely distributed throughout the whole of the 

 South Pacific Ocean. 



