74 NEW ZEALAND NEUBOPTEBA. 



This insect is, in fact, very hardy, and can easily be kept 

 in a shallow vessel of water, if it is supplied with a few 

 leaves and twigs from its native stream. The larva may 

 be found in the streams throughout the entire year, but it 

 is most abundant about midsummer. 



When extracted from its singular habitation the larva of P. obsoleta is 

 not found to differ widely from many other caddis-worms (fig. 2). The head 

 and first two thoracic segments are rather small, horny, and dark brown in 

 colour ; the two anterior pairs of legs are short, pale yellow barred with dark 

 brown ; the posterior legs are very long and are chiefly instrumental in 

 moving the larva and its case. They project forwards from the case, and 

 act somewhat as a pair of grappling-hooks. The last thoracic segment is of 

 large size, and has four horny dorsal plates. The first segment of the 

 abdomen is furnished with a very large dorsal hump. All the segments 

 of the abdomen are very large, soft, and yellowish-white in colour. There 

 are seven pairs of respiratory filaments on each side of the larva. The 

 anal hooks are small, and each is situated on a moderately large protu- 

 berance. There is a number of stout bristles on the last two segments 

 of the insect. 



As soon as this larva has attained its full size, it 

 fastens one end of its habitation securely to a log or 

 other firm object, and closes both of the orifices with a 

 loosely spun silken lid, means being thus provided for the 

 free circulation of fresh water through the case for the 

 use of the enclosed insect whilst it is in the pupa state. 



The pupa is a most beautiful object. Its length is about § inch. The 

 jaws are small and prominent, the eyes very conspicuous ; the head and 

 thorax are brown, the abdomen ochreous-yellow. Legs and palpi brown. 

 Eespiratory filaments are situated on all the segments of the abdomen, 

 except the last three. The extremely long antennse are carried in two spirals 

 beyond the end of the body. 



The pupa is enclosed in a thin, tough cocoon inside 

 the hollow stick or wooden case, which is firmly attached 

 to a sunken log in the stream. 



The insect remains in this condition for three or four 

 weeks. About twenty-four hours before its final trans- 

 formation the pupa leaves its old habitation and swims 

 about in the water with considerable rapidity. After this 

 the emergence of the imago takes place, but the insect's 

 exact procedure during this operation is not quite clear. 

 Probably the pupa does not leave its native element 

 before emergence, as the empty pupa skin is always 

 found floating on the surface of the water. The perfect 

 insect appears from November till March. It is often 

 common in the vicinity of forest streams, and may be 

 captured at evening dusk. It flies with a peculiar zigzag" 

 flight, but in this respect it is not nearly so remarkable 

 as the next species. It is also attracted by light. I have 



