Miller. — The Dipt era Fauna of New Zealand. 311 



P. atkinsoni n. sp.* 



<J. A slender black fly with 4 pairs of white spots on the abdomen, and 

 emerald-green halteres. 



Head in profile decidedly flat above, the front curved down to antennae 

 (fig. 47) ; eyes bare, holoptic, the posterior margin concave ; ocellar tri- 

 angle black and clothed with blackish hairs ; ocelli vermilion ; front pale 

 tawny, clothed with black hairs, a short median brownish stripe extending 

 on to front from confluence of eyes ; lunular area testaceous with a blackish 

 spot on the middle, bi-crescentic. Antennae broadly separated, inserted 

 in pits well up on head ; 1st and 2nd joints blackish-brown with a greyish 

 reflection ; 3rd joint ovate, brick-red with a blackish upper margin and 

 covered by a silvery tomentum ; arista black. Face as shown in fig. 47 ; 

 a broad black median stripe, narrowing at oral margin, which it narrowly 

 borders ; on each side this stripe merges into testaceous, which in turn merges 

 into the pale yellowish-green of face ; insertion of each antennae surrounded 

 by a pale-yellow area ; a brownish-black spot extends from oral margin 

 in front of cheeks to a point on lower eye-margin ; face greyish-pruinose 

 on each side and between and immediately below the antennae, and clothed 

 with short tawny hairs except on blackish areas ; orbito-facial groove pro- 

 nounced ; cheeks rather swollen, black with a greyish reflection, and clothed 

 with short whitish hairs ; occiput black, the orbits clothed with short white 

 hairs ; mouth-parts black, but the labella orange-brown. 



Thorax shiny black, clothed with silvery hairs more scattered on the 

 dorsum, on each side of which is a greyish area extending from a point at 

 humerus, widening into incison of transverse suture and thence narrowing 

 to the wing ; scutellum dull brownish-yellow, margined with black and 

 clothed with blackish hairs ; the meso-, ptero-, and upper part of sterno- 

 pleurae greyish-pruinose and clothed with long silvery hairs ; remainder 

 of pleurae black ; halteres with brown shafts and large emerald-green 

 heads. Wings clear, the stigma orange-brown, veins black ; squamae opal- 

 white and fringed with silvery hairs. Legs slender, the posterior tibiae 

 and protarsi slightly thickened ; anterior and middle tibiae sparsely clothed 

 with stiff brownish hairs, orange-brown but lighter at the apex ; posterior 

 coxae black, greyish-pruinose, and clothed with silvery hairs ; posterior 

 femora blackish-brown, greyish in some lights, rather tawny at apex, and 

 sparsely clothed with silvery hairs which are denser below distally ; anterior 

 and middle tibiae orange-brown, darker in some lights, the latter with 

 minute black apical bristles below ; posterior tibiae blackish-brown, paler 

 basally and with a greyish reflection ; anterior and middle tarsi blackish- 

 brown, clothed with short silvery hairs, the former rather broadened, the 

 protarsi of the latter with minute bristles beneath ; posterior tarsi black 

 with short golden hairs beneath, the protarsi somewhat thickened ; all 

 the tarsal joints bristly at angles ; claws orange-brown with black tips ; 

 pul villi orange-brown. 



Abdomen (fig. 58) elongate, narrow, parallel-sided, shiny black, sparsely 

 clothed with short silvery hairs which become longer at sides particularly 

 on basal segments, but shortening and not extending to apex of 4th seg- 

 ment, their place being taken by small black bristles ; 2nd, 3rd, 4th, and 

 5th segments each with a pair of oblique white spots, those of 2nd segment 

 truncated above, and of the 5th somewhat yellow ; genitalia greyish-yellow. 



<$. Length, 9 mm. 



Holotype : No. 1250, D. M. 



Habitat. — Devil's Punch Bowl, Arthur's Pass (E. H. Atkinson). 



* Named after Mr. E. H. Atkinson, of Wellington. 



