Massalongia betulifolia Harris, 1974

Elsayed, Ayman Khamis, Skuhrava, Marcela, Ohta, Kazuki, Yoshida, Satoshi & Tokuda, Makoto, 2020, Revision of the birch-associated genus Massalongia (Diptera, Cecidomyiidae), with description of a new species from Japan and a taxonomic key to worldwide species, ZooKeys 958, pp. 1-27 : 1

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 .

Figures

Figures 43 - 47. Massalongia betulifolia. 43 head 44 ventral view of mouthparts (hypopharynx is folded). 45 dorsal view of male flagellomere VIII 46 wing 47 tarsomere V and acromere. Scale bars: 50 µm.

Figures 48 - 49. Massalongia betulifolia. 48 terminal part of female abdomen (arrow indicate the dorsal sclerite on the protrusible portion) 49 protrusible portion of ovipositor. Scale bars: 50 µm.

Figures 50 - 51. Massalongia betulifolia. 50 male terminalia 51 ventral view of male hypoproct and aedeagus. Scale bars: 50 µm.