Discobola tesselata (Osten-Sacken.) (Figs. 33, 34.)
Trochobola tesselata Osten-Sacken, Berlin. ent. Zeitschr., vol. 39, p. 266, 1894.
Trochobola variegata Hutton, Trans. N.Z. Inst., vol. 32, p. 36, 1900.
Limnobia tesselata Walker (nom. nud.), List Dipt. Brit. Mus., vol. 1, p. 45, 1848.
This species differs from all the others as yet known from New Zealand in the predominating light-ochreous colour of thorax and abdomen. Praescutum has four dark stripes, middle pair narrow and widely separated; postnotum has a blackish band down middle. Hypopygium has claspers resembling those of Dicranomyia—a slender, curved, horny upper pair, and a fleshy lower pair provided with an inwardly-projecting rostrum; rostrum does not bear spines, but there is a pair of straight slender rods on the fleshy clasper itself near base of rostrum. Quite distinct from D. australis; it has not the strongly produced praescutum of that species, and differs in many details of coloration.
The name tesselata must be attributed to Osten-Sacken, who gave a very brief diagnosis of Walker's specimen; this was just sufficient to validate the name, and necessitates sinking Hutton's T. variegata as a synonym. The species is extremely similar to the North American D. argus and the European D. annulata—more so than to any other New Zealand species.
North Island: Wellington district (G. V. Hudson, No. 229). Walker's specimen (a male) is unlabelled as to locality. There are also two females in British Museum, presented by Mr. Hudson.