296 Transactions. 



Habitat. — L. decessum is found throughout New Zealand, and occurs 

 on the wing from September to May ; it is most prevalent in the vicinity 

 of flax-bushes (Phormium tenax) and cabbage-trees (Cordyline australis), 

 which are the breeding-grounds of the larvae. All larval stages are to be 

 found at the one time inhabiting the gum-fluid retained in the leaf-sheaths 

 of P. tenax ; the larval period, particularly during the colder months, is 

 of considerable duration. Pupation occurs upon the dead flax-leaves, to 

 which the pupae adhere ; they are partially or completely covered by a 

 white precipitate from the gum-fluid. Mr. G. V. Hudson* has found the 

 larvae of this fly breeding in decaying matter under the bark of cabbage- 

 trees. 



cj and $. Length, 7 mm. 



Holotypes : $, Hutton's collection, Canterbury Museum ; #, No. 1232, 

 D. M. 



Genus Sphaerophoria St. Far. et Serv. (1828). 



Species of slender body ; eyes bare ; 3rd antennal joint circular ; 

 abdomen elongate, rather narrow and restricted at base in the male ; 

 wings somewhat elongate. 



S. ventralis n. sp. 



A small slender black fly with 4 tawny spots on the abdomen ; legs, 

 pleurae, and face yellow ; apex of wing clouded. 



cj. Eyes bare, approximated on vertex, which, together with the ocellar 

 triangle, is shiny blue-black ; ocelli vermilion ; upper part of front shiny 

 blue-black, the anterior margin of this colour being trifid, the central fork 

 largest, the lateral ones short and extending to orbits ; lower front pale 

 yellow, somewhat greenish and widening to lunule, which is dark yellow ; 

 front and veitex clothed with short and erect brownish hairs. Antennae 

 short and tawny ; 3rd joint circular with a black upper edge ; arista black. 

 Face vertical below antennae but produced above oral margin (fig. 10) 

 bare and shiny pale yellow with a dark-brown central spot on protuberance 

 cheeks pale yellow and clothed with short pale hairs ; occiput black 

 proboscis and palpi dark yellow. 



Dorsum of thorax shiny black-brown, tawny on alar calli and on each 

 side posterior to transverse suture ; humeri, pleurae, and halteres tawny ; 

 scutellum brown ; legs tawny, the posterior tarsi somewhat darker. Wings 

 more or less blunt at apex ; a brown cloud at apex between veins E t 

 and R 4 + 5 ; articulation tawny; wings otherwise clear and iridescent; 

 squamae tawny. (Plate XLVII, fig. 6.) 



Abdomen (fig. 13) shiny blackish-brown, elongate and narrow, somewhat 

 narrowed basally ; 1st segment with a tawny tuberculate swelling on each 

 side of scutellum ; 3rd and 4th segments each w T ith a pair of elongate dark- 

 yellow spots directed upward from the sides toward the centre ; genitalia 

 brownish-yellow. 



cJ. Length, 6-5 mm. 



Holotype : No. 273, D. M. 



Habitat. — Purakanu i . 



* Trans. N.Z. Inst., vol. 52, p. 34 (1920) 



