Myopa testacea Species-Group

Stuke, Jens-Hermann & Clements, David K., 2008, Revision of the Myopa testacea Species-Group in the Palaearctic Region (Diptera: Conopidae), Zootaxa 1713, pp. 1-26 : 2-3

The Myopa testacea Species-Group

The testacea -group is, together with the closely related polystigma -group, distinguished from all other Myopa species-groups by the following combination of characters: (1) conspicuous white hairs on the ventral occiput (i.e. white ‘cheek whiskers’); (2) the crossvein r-m is black, and usually lies within a conspicuous blackish wing marking; and (3) the absence of a conspicuous, dense and isolated wing marking in the centre of cell r4+5. Segregation of the testacea -group from the polystigma -group is more difficult, although this is normally possible through the more strongly spotted wings of the latter. In the polystigma -group there is normally blackish marking of the wing membrane along much of the length of vein M, but the marking along the outer section of this vein (M2) is usually obviously interrupted in the middle section so as to produce distinct and obviously isolated spots at the wing apex and at the junction of M2 with the outer crossvein dm-cu ( Fig. 2 ). In the testacea -group these markings are either absent entirely ( Fig. 1 ), or if present then the blackish coloration along vein M2 runs uninterrupted from the outer crossvein dm-cu to the wing apex. This distinction is sometimes unclear in Myopa vicaria Walker, 1849 which is currently considered to belong to the polystigma -group, but this species also differs from the testacea -group in lacking any distinct rows of setose bristles in the basal part of the undersides of tibiae 1 and 2. Myopa vicaria is usually also distinctive in having very long hairs on the body, the longest of which are clearly longer than the hind metatarsus, as well as in having markedly pale (i.e. yellowish-orange) abdominal coloration.

These two species-groups have been separated as a matter of expediency and probably do not form natural taxonomic groupings. Their maintenance may therefore eventually prove to be unsustainable. However, their separation is presently invoked in order to allow the early revision of the testacea -group.

As far as can be ascertained, all species of the testacea -group are univoltine and fly mainly in the spring months, although at higher altitudes and in northern areas especially, the flight period may extend until July or later. The testacea -group appears to be confined to the Palaearctic region.

Figures

FIGURES 1 – 2: Wing of Myopa. — 1: testacea Linnaeus, [Germany, Berlin, Forst Düppel]; — 2: polystigma Rondani, 1857 [Germany, Ldk Uelzen, Galgenberg / Grünhagen].