32 NEW ZEALAND NEUROPTEBA. 



being discovered under a single boulder. They are 

 seldom seen swimming in the open, or walking on the 

 upper surfaces of the stones, and it is probable that, but 

 for their secretive habits, their numerous enemies would 

 speedily exterminate them. These larvae are equally 

 common throughout the entire year, and are always to 

 be found in all stages of growth ; mature individuals are, 

 however, most abundant during the summer months. 

 The larvae of this species, and, in fact, those of the 

 genus Atalophlebia generally, constitute one of the 

 most important of the various food supplies afforded to 

 trout by our native Neuroptera. Although individually 

 small, these larvae are so numerous that they are prob- 

 ably far more valuable as fish food than the larvae of 

 many of the larger but rarer species, and the fact that 

 they are plentiful at all seasons is a great additional 

 advantage. The importance of these insects in their 

 relation to the cultivation of trout in our streams will, 

 I think, be fully appreciated after an examination of the 

 tables, showing the various species of insects devoured 

 by trout, given in the Appendix. 



The full-grown larva of A. dentata measures about i inch in length, 

 exclusive of any appendages. The head is large, somewhat quadrangular, 

 with the eyes black and very prominent ; the prothorax is very broad and 

 almost rectangular. The remaining segments of the thorax taper some- 

 what, and the wing-pads are rather small. There are seven double pairs 

 of gills on the abdomen, which are kept almost continuously in motion by 

 the larva. Each gill is oval in shape and very pointed at the apex (see 

 Plate XL, fig. 18). The femora of all the legs are oval and very stout. The 

 tails are very slender, considerably longer than the body, the middle tail 

 being the longest. The general colour of the insect is dull brown with 

 black markings. 



When about to emerge, this larva crawls out of the 

 water on to a dry stone, and the winged insect escapes 

 in the usual manner. 



The sub-imago is very much paler and duller in colour 

 than the imago. The wings are uniformly shaded with 

 dull brown, with the neuration blackish. The insect 

 remains in this state for about two days, during which 

 time it is usually completely quiescent. 



The perfect May-fly is found in thousands over the 

 streams during the entire summer, but is most abundant 

 during October and November. It flies in groups of a 

 dozen or more with the characteristic up-and-down flight. 

 These groups can readily be seen projected against the 

 bright evening sky, but are generally out of reach of the 

 net. Occasionally, however, a group will descend a little 



