Massalongia betulifolia Harris, 1974

Description.

Head (Figs 43-45). Eyes separated on vertex by diameter of 0.5-1.25 facets. Frons with 7-12 setae (n = 5). Mouthparts: labrum with 6-11 short setae (n = 5), hypopharynx pointed, covered with thick microtrichia; labellum with 5-8 stout setae (n = 4) laterally. Antenna: scape and pedicel with few ventral setae on basal third of segment.

Thorax (Figs 46, 47). Wing 2.8-3.0 mm long in males (n = 2), 3.1-3.2 mm in females (n = 2). Anepimeral setae 6-10 (n = 6).

Female abdomen (Figs 48, 49). Tergites I-VI bare posteromedially; tergite VII with entire posterior row of setae. Ovipositor: protrusible portion with, ca. 2 times as long as tergite VII, with dorsal sclerite almost along dorsal portion; cerci setose.

Male abdomen. Tergites I-VII as in female; tergite VIII with few setae posteriorly. Terminalia (Figs 50, 51): gonostylus with blunt denticles; cerci base with few setae; cerci with setae apically; hypoproct entire, narrowed at midlength; aedeagus shorter than cerci and hypoproct, cylindrical in dorsoventral view, wide basally in lateral view.

Mature larva. Spatula absent. Terminal segment with short conical papillae (Harris 1974).

Pupa. Exuviae generally unpigmented. Antennal horns short (Askew and Ruse 1974).

Materials examined. Holotype (BMNH): 1♂, emerged on vi.1971, reared by J. Ruse from larva forming lamina and midrib blister galls on Betula pendula leaves, collected on x.1970 from Lindow Common, Cheshire, England. Paratypes: 4♂, 2♀, data same as for holotype.

Distribution.

Europe: England and Norway ( Gagné and Jaschhof 2017).

Gall and life history.

Massalongia betulifolia forms blister-like leaf galls on B. pendula and B. pubescens . Galls are formed usually between or on veins and are 2.5-3.0 mm wide and 5.0-6.0 mm long. Mature larvae drop to the ground to overwinter in cocoons. Adults emerge probably in May and June, and the galls can be found on the trees between June to October (Harris 1974; Askew and Ruse 1974).

Remarks.

See Remarks under M. bachmaieri and M. nakamuratetsui .