Megaselia comparabilis Schmitz, 1929

DISNEY, R. H. L., 2003, Tasmanian Phoridae (Diptera) and some additional Australasian species, Journal of Natural History 37 (5), pp. 505-639 : 538-541

Megaselia comparabilis Schmitz, 1929

(figure 15)

Megaselia comparabilis Schmitz, 1929: 115 .

Megaselia dissita Borgmeier, 1967a: 314 . Syn. nov.

Aphiochaeta nebulosa White, 1917: 259 ; nec (Walker, 1857: 234).

Megaselia dissita was described from a single male from Hobart. I have remounted this on a slide. It proves to be the same as a series of specimens that White (1917) attributed to the species described by Walker (1857) as Phora nebulosa . Borgmeier (1967b) had listed Walker’s species as incertae sedis, as neither Walker’s nor White’s descriptions allow recognition of either the genus or the species. The whereabouts of Walker’s specimen has not been discovered. Borgmeier (1968) subsequently listed the species as Megaselia nebulosa (Walker) , after being informed that the mesopleura of White’s series (which is in the Natural History Museum, London) were hairy. However, despite the deficiencies of both descriptions, the stated differences in the colours of the legs and wings are sufficient to indicate that these two descriptions do not refer to the same species. This is confirmed by the measurements given by Walker, who stated that the ‘length of wings’ was 4 lines and the body length was 2.5 lines. In metric units these figures would be 8.5 mm and 5.3 mm. ‘Length of wings’ must mean the distance between the wing tips when the wings are set perpendicular to the main axis of the body. If one allows up to 1 mm for the width of the thorax then the minimum length of a wing would be 3 mm. I have remounted White’s series on slides. The maximum wing length, of the largest female, is 3.1 mm but the body length of all four specimens is less than 5 mm. I conclude that White’s series represents a different species. Walker’s species must therefore be designated a species indeterminata. White’s male is the same as that subsequently descibed by Borgmeier under the name M. dissita . His females, however, belong to M. comparabilis , which Schmitz described from three females from New Zealand. Bridarolli (1937) subsequently described the males. However, his series is mixed, as I discovered when I remounted a female on a slide (see under M. impariseta below). A remounted male from his series (labelled Nelson 8.V.22 A. Tonnoir) proved to be M. dissita . However, I have also remounted a pair from the New Zealand Arthropod Collection (labelled ‘ Auckland, Oratia. 4 June 1949 R. Harrison’), which were caught in copula. The male is Borgmeier’s M. dissita but the female is Schmitz’s M. comparabilis . Furthermore, this female is the same as those in White’s series. It is concluded, therefore, that M. dissita is a synonym of M. comparabilis .

Material

One male and 3 females, Tasmania , Mangalore, on window, 12 May 1913 (A. White — BM1917-104 ) ( NHM, London). Male , Mt Field National Park, Russell Falls, 26 December 1991 ( R. H. L. Disney —25-5) ( UMZC) ; 11 males, Fern Tree , near Hobart, Grays Road, at window of builder’s shed, 18, 22 September 1998 ( RHLD —25-23, 25-28) ( UMZC, TMH) .