MAY -FLIES. 23 



lengthened period, as they were disturbed during the 

 process. 



Whilst submerged the female is covered with a 

 coating of air, which of course looks silvery-white 

 below the water. This air is, no doubt, retained by 

 the integument, assisted by the numerous bristles and 

 hairs which are situated thereon. 



XANTHAGRION ANTIPODUM. 



Xanthagrion antipodum, de Selys, Synopsis Agrionines, 

 p. 239 (1876). 



"Differs from X. zealandicum in having no spots behind the eyes, but 

 a yellow occipital line only, and no yellow spots on the prothorax ; the first 

 abdominal segment has no yellow spot ; the femora have a black ray on the 

 outside. There are only 11 post-nodal nervules. The pterostigma is rather 

 shorter than the opposite cell. Length of the abdomen, 24 mm. ; of the 

 hind-wing, 17 mm. 



" Locality. — New Zealand. 



"Described from a single female specimen" (Hutton). 



I am unacquainted with this species. It appears to 

 be very closely allied to Xanthagrion zealandicum. 



XANTHAGRION SOBRINUM. 



Telebasis sobrina, McLachlan, Ann. Nat. Hist., ser. 4, 

 vol. 12, p. 36 (1873). Xanthagrion sobrinum, de Selys, 

 Synopsis Agrionines, p. '234 (1876). 



"Very like X. zealandicum, but larger; the basal spot on the first 

 segment of the abdomen is divided ; the superior anal appendages are 

 much exserted, scarcely half the length of the inferior, sub-triangular, 

 the lower edge concave. Four cellules between the quadrilateral and the 

 nodus in all the wings ; 'pterostigma surmounting fully two cellules; anterior 

 wings with 15 post-nodal nervules. Length, 39 mm. ; of abdomen, 31 mm.; 

 of hind-wing, 22 mm. ; expanse, 56 mm. 



" Locality. — New Zealand and Chatham Islands. 



"In Chatham Island specimens the basal black spot on the first 

 abdominal segment is not divided, and there are 15 to 18 post-nodal 

 nervules" (Hutton). 



Family VII.— EPHEMERIDiE- MAY-FLIES. 



" Delicate insects with atrophied month and small, 

 short antenna; with four membranous wings having 

 much minute cross-veining ; the hinder pair very much 

 smaller than the other pair, sometimes entirely absent : 

 the body terminated by three or two very elongate slender 

 tails. The earlier stages are passed through in the water, 

 and the individual then differs greatly in appearance from 



