MAY-FLIES. 43 



serratures are broader, and are rather more produced at the point than the 

 third " (Eaton). 



Respecting the extreme rarity of this insect at the 

 present time, Captain Hutton remarks as follows : — 



"In 1874 this insect was common in the neighbour- 

 hood of Christchurch. I have lived there during the 

 last nineteen years without seeing a single specimen. 

 Whether they have been killed off by the trout or by the 

 sparrows I cannot say." 



I am unacquainted with this interesting insect. 



ONISCIGASTER INTERMEDIUS. 



Oniscigaster intermedins, Eaton, Trans. Ent. Soc. 

 Lond., 1899, 292, pi. x., 6a detail. 



In the North Island this species occurs in a certain 

 restricted spot near Wellington, and I once captured a 

 single specimen on the Tableland of Mount Arthur in 

 the South Island, at an elevation of 3,600 feet above the 

 sea-level. 



Concerning the specific character of this May-fly 

 Eaton says : — ■ 



" A single female imago differs from 0. wakefieldi in having only two 

 dorsal segments, viz., the eighth and ninth, dilated laterally, and this only 

 moderately ; back sub-fornicate above the dilatation. Lateral borders of 

 eighth segment almost straight, except where they gently curve inwards 

 near the base, and very nearly parallel, diverging only to a very small 

 extent posteriorly ; back transverse at the posterior margin ; the postero- 

 lateral angles obtuse. Ninth segment as broad or perhaps a little broader 

 than the eighth ; its lateral margins saliently curved, and bordered each by 

 a linear flange terminating posteriorly in a minute point ; the posterior 

 margin of the dorsum transverse between these points. Wings marked as- 

 in 0. wakefieldi." 



The transformations of this insect closely resemble 

 those of the next species. 



ONISCIGASTER DISTANS. 



Oniscigaster distans, Eaton, Trans. Ent. Soc. Lond.,. 

 1899, 293, pi. x., (jb and 6c. 



(Plate I., fig. 9 ? , 10 ditto, sub-imago, 11 nymph 

 enlarged.) 



This handsome species has been found at Wainui-o- 

 mata, near Wellington. 



The expansion of the wings of the male is 1$ inches, of the female 

 1J inches. The general colour in both sexes is blackish-brown and very 



