MAY-FLIES. m 



lower than usual, when quite a number of specimens 

 may often be secured together. 



ATALOPHLEBIA CRUENTATA, n. sp. 

 (Plate I., fig. 6 nymph magnified.) 



The imago of this species very closely resembles that 

 of A. dentata, but is generally rather smaller, the colour- 

 ing is paler and the costal shading of the fore-wings is. 

 orange-yellow in place of red. 



The nymph of this insect is found commonly in all! 

 the streams in the vicinity of AVellington, but is not 

 nearly so abundant as those of either of the two preceding 

 species. It lives amongst the sandy debris in the bed 

 of the stream, and is therefore often rather difficult to> 

 obtain. On lifting up a large stone this larva either 

 immediately secretes itself amongst the smaller stones 

 underneath, or else clings so closely to the surface of the 

 large stone that it is very difficult to detect, and thus 

 frequently escapes capture. By adopting these tactics 

 it must very often elude fish and other enemies, and on 

 this account alone, apart from its comparative rarity, I 

 do not think that it forms at all an important article of 

 food so far as the trout are concerned. 



The length of the nymph when full grown is about J inch. Its general 

 colour is bright orange-red. The head and prothorax are rather small and 

 narrow. The wing-pads are of moderate size and black in colour. The 

 legs are rather long and slender, and the anterior pair have two black bands. 

 The abdomen has a dark line down the middle ; it is furnished with six 

 pairs of small double gills, which are constantly vibrated by the larva for 

 respiratory purposes. 



This larva usually frequents rather slow-running 

 portions of the stream, generally near the bank. It is 

 very hardy in an aquarium. In fact, a constant supply 

 of swift-running water does not seem so essential to its 

 welfare as it does in the case of nymphs belonging to 

 the other members of the genus. 



The sub-imago of this species very closely resembles 

 that of A. dentata, but the brown colouring of the wings 

 is slightly darker. As a matter of fact, neither the 

 imago nor the sub-imago of these two May-flies can be 

 separated with certainty, unless a very careful and special 

 examination is made of them, but the obvious differences, 

 which are exhibited by their respective nymphs, ensure 

 their immediate and certain recognition during that stage 

 of their existence. 



4 



