Megaselia henrydisneyi Durska, 1998

Disney, R. H. L. & Russell-Smith, A., 2014, Additions to the British list of Megaselia Rondani (Diptera: Phoridae), including two new species, from the crowns of ancient pollarded trees, Journal of Natural History 49 (25), pp. 1599-1626 : 1603-1607

Megaselia henrydisneyi Durska

( Figures 4–6 )

Megaselia henrydisneyi Durska, in Disney and Durska 1998, p. 437 (male)

The recognition of this species was initially impeded by the badly faded condition of the type series from Poland when compared with the fresh material from England, and by two errors in the original description. The latter included it being abdominal tergite 6, as opposed to T2 being longer than the rest of the abdominal tergites, and a pair of prescutellar dorsocentral bristles being present rather than absent. In some specimens these bristles are indeed lost, but their basal sockets are present. Critical details of the male are given in Figures 4–5 . The hitherto unknown female is described below .

Female

Head similar to male except labrum is about 1.4 times wider than diameter of postpedicel and the palp about 0.4–0.5 times as wide but 1.8 times as long as the latter. Labella paler, with submarginal pale greyish bands above and very few bristles reduced to small spinules below. Otherwise head similar to male. Thorax as male. Abdominal tergites brown. T5–T7 as Figure 6C . Venter grey, and with hairs below segments 3–6. Sternite 7 a narrow triangle, but of irregular outline, with five to 10 hairs. Posterolateral lobes at rear of sternum 8 as Figure 6B . Cerci lightly tinged brown and as Figure 6A . Furca not evident. Dufour’ s crop mechanism about twice as long as greatest width and rounded behind. Legs similar to male but the front tarsus is more slender and about 1.5 times as long as that of the male. Wing as male except 1.87–2.14 mm long. Costal index 0.49–0.50. Costal ratios 2.8– 3.6:1.6–2.0:1. Costal cilia 0.14–0.16 mm long. With five axillary bristles. Otherwise it and haltere as male.

One female was gravid with 40 eggs that measure 0.32 mm long and 0.13–0.14 mm wide.

Material

Obtained in pitfall traps in crowns of old pollards at the following localities. Berkshire, Windsor Great Park, (grid ref. SU 9872), Bear Rails, crowns of old oaks ( Quercus spp.), 22.vi–13.vii.2012; Buckinghamshire, Burnham Beeches, 2–31.

v.2012; Essex, Hatfield Forest (grid ref. TL5319 ), 22.v–15.vi.2012 ; Kent, Merton Hatch, Bockhanger Wood , hornbeam ( Carpinus betulus ), 14.v.–9.vi.2012 .

Recognition

In the keys to the males of British species ( Disney 1989), the males run to couplets 79– 81, which are revised below.

Figures

Figure 4. Megaselia henrydisneyi male, hypopygium. (A) Left face; (B) right face. Scale bar: 0.1 mm.

Figure 5. Megaselia henrydisneyi male. (A) Frons (with bristles represented by their basal sockets only); (B) right face of hypopygium; (C) left face of hypopygium. Scale bars: 0.1 mm.

Figure 6. Megaselia henrydisneyi female, details of abdomen. (A) Left cercus; (B) lobes at rear of sternum 8; (C) tergites 5–7. Scale bars: 0.1 mm.