THE NEUROPTERA. 101 



With regard to the method employed by the young 

 larva in constructing, and subsequently enlarging, its case, 

 I can give no positive information, although it is un- 

 doubtedly made of a viscous fluid, secreted by the insect, 

 which hardens when exposed to the water ; this secretion 

 is no doubt analogous to the silk of caterpillars, which 

 always exists in the form of a gummy fluid before being 

 spun. 



When about to change, the insect fixes its case down by 

 four ligaments, two at each end, the extremities of these 

 being firmly fastened to a stone ; it then closes the 

 small aperture, and constructs a curious arch-shaped 

 partition, of dense material, a short distance from the 

 broad end (Fig. 3b). In about a week's time the larva is 

 transformed into a pupa, having the limbs, &c, free from 

 the body but incapable of motion. The fixing down of 

 the case prior to the change may be easily performed 

 from each of the apertures, which are no doubt left 

 open till the last for this purpose. Before the final trans- 

 formation the pupa breaks through the partition at the 

 broad end of the case and rises to the surface, the 

 imago (Fig. 3) ascending a blade of grass to dry and 

 expand its wings. The little exuvia of the pupa may 

 be often noticed floating on the water, and the empty 

 cases are very conspicuous on the sides of a glass 

 aquarium, where the insects generally fix them down 

 when in captivity. 



Family HEMEROBIID^E. 



Stenosmylus incisus (Plate XIV., fig. 2). 



This lovely insect is figured as an example of this family, 

 being found occasionally in the New Zealand forest, but is 

 rather scarce as a rule. I regret that nothing is at present 

 known of its transformations. 



