86 NEW ZEALAND NEUBOFTEBA. 



HYDROBIOSIS FRATER. 



Hijdrobiosis f rater, McLachlan, Journ. Linn. Soc, 

 vol. 10, p. 207, 'pi. 2, figs. 9a, 96 (1870). 



This species has occurred at Nelson and at Christ- 

 church. 



The expansion of the wings is about j| inch. 



"Brown; antennae brown with narrow yellowish rings ; vertex blackish, 

 with dark-grey hairs ; ocelli large, yellowish. Anterior wings with long- 

 woolly black and grey hairs ; pterostigma elongate, brown ; a space on the 

 middle of the dorsal margin pale grey, tufts of longer black hairs along 

 the dorsal margin of the male only. Posterior wings sub-hyaline, the 

 fringes blackish. Legs dull-red ; anterior and intermediate tibia? with a 

 narrow median pale ring. Abdomen brown, yellowish beneath ; the male 

 with three ventral teeth. Length of the body, <? 5 mm., $ 7 mm. ; expanse 

 of the wings, g 18 mm., ? 23 mm." (Hutton). 



In February, 1892, I found this insect in great 

 abundance on the banks of the Buller River, where it 

 flows out of Lake Rotoiti. 



HYDROBIOSIS UMBRIPENNIS. 



Hijdrobiosis umbripcnnis, McLachlan, Journ. Linn. 

 Soc, vol. 10, p. 208, pi. 2, figs. 9c, 9d (1870). 



(Plate XL, fig. 11, 12 larva, enlarged; 13 pupa enclosed 

 in its inner cocoon, enlarged.) 



At present specimens of this insect are only recorded 

 from Wellington, Nelson, and Christchurch ; but future 

 investigation will probably prove that it is generally dis- 

 tributed throughout the country. 



The expansion of the wings is from ^ to 1 inch. 



"Brown; antennae yellow, with indistinct brown rings; ocelli large and 

 conspicuous, yellow. Anterior wings brown, with blackish and whitish hairs; 

 pterostigma darker, elongate; neuration pale yellowish-testaceous, apical 

 fringe with yellowish dots and tufts of black hairs along the cubitus near 

 the base. Legs pale testaceous ; the anterior tibia? and tarsi rather brownish 

 externally, with paler rings. Abdomen brown above, yellowish beneath ; the 

 male with but one ventral tooth, which is long, on the apical margin of the 

 penultimate segment. Length of the body, g 8 mm., ? 11 mm.; expanse 

 of the wings, <? 32 mm., ? 27 mm." (Hutton). 



The larva of this insect inhabits clear, rapid streams, 

 and swims with great activity amongst the stones. It is 

 carnivorous, chiefly feeding on small May-fly larva?. The 

 larva? of H. umbripennis are found in the streams during 

 the entire year, but are commonest in the spring and early 

 summer, only very small specimens occurring in the 

 autumn and early winter. 



