Mitodiplosis Kieffer, 1914

Kolesik, Peter & Wood, Alan R., 2019, Redescription of Mitodiplosis graminis (Diptera: Cecidomyiidae), a gall midge inhibiting the flowering of pyp grass Ehrharta villosa (Poaceae) in South Africa, Zootaxa 4614 (1), pp. 173-179 : 174

Genus Mitodiplosis Kieffer

Mitodiplosis Kieffer, 1914: 516 .

Type species: Mitodiplosis graminis Kieffer (orig. des.).

Mitodiplosis contains a single species, M. graminis Kieffer.

Diagnosis. The wing vein R 5 is bowed at its distal end, joining C posteriad to the wing apex; R S is reduced to a thickening at a bend of R 5, R 1 joins C beyond midlength of wing ( Fig. 2i ). The adult head has small mouthparts with a hemispherical labrum and merged labella and bears no occipital protuberance ( Fig. 2a ). The antennae have 12 flagellomeres which in the male are binodal, with one separate whorl of many-looped circumfila on the basal node and two separate whorls of loops on the distal node ( Fig. 2e, f ). In the female the flagellomeres are cylindrical, slightly constricted at mid-length, with two separate whorls of circumfilar loops ( Fig. 2g ). The sockets of male and female circumfilar loops are positioned on the surface of the flagellomere in a non-planar fashion, giving the circumfila an irregular appearance. The maxillary palpus consists of two segments, the first is wide and short, the second narrow and extremely long, with a constriction suggesting a fusion of two segments ( Fig. 2h ) and thus can be also interpreted as a three-segmented palpus. The maxillary palpi were partially folded underneath head in most specimens we mounted and therefore we examined the palpi of adults inside mature pupae where they were unfolded. The tarsal claws are simple an all legs, bent at distal ¼ and the empodia are longer than the claws ( Figs 2j, k ). Abdominal tergites have an anterior pair of sensory setae. The male terminalia ( Figs 2 b–d) have a robust gonocoxite with basally merged gonocoxal apodemes, a gonostyle that is wide at the base and tapering towards a large dorso-distal claw, a long aedeagus with asetose apical sensoria, large rounded triangular cerci and a hypoproct that is blunt posteriorly and bears on either side a small postero-lateral lobe with several setae ( Fig. 2d ). The female terminalia ( Figs 2l, n ) are short, not protractible, the cerci are separated, large, ovoid, covered with dense setulae and bearing many setae. The larva has a strongly reduced setation, while the spatula is well developed ( Fig. 3h ). The pupa has a cylindrically shaped facial horn ( Figs 3a, b, d ). The adults differ from the other Cecidomyiidi genera in the combination of the following characters: reduced mouthparts, large dorso-distal claw on the gonostyle, the shape of the male hypoproct, the shape of the maxillary palpus and unusually robust microtrichia covering the head and the thorax. Mitodiplosis belongs to the supertribe Cecidomyiidi but cannot be accommodated in any of the 11 currently recognised tribes (sensu Gagné & Jaschhof 2017).

Figures

FIGURE 2. Mitodiplosis graminis. a–f: male, g–n: female. (a) head, (b) terminalia in dorsal view, (c) gonostyle in ventral view, (d) hypoproct in dorsal view, (d) fifth flagellomere in dorsal view, (e) fifth flagellomere in dorsal view, (f) fifth flagellomere in ventral view, (g) fifth flagellomere in lateral view, (h) palpi of four separate specimens inside pupa, (i) wing, (j) tarsal claws with empodium and pulvilli in ventral view, (k) tarsal claw with empodium and pulvillus in lateral view of specimens inside pupa, (l) terminalia in ventral view (position of omitted setae indicated with arrows), (m) first tarsomere, (n) terminalia in lateral view.

FIGURE 3. Mitodiplosis graminis. a–d: pupa, e–h: larva, i: egg. (a) anterior part ventrally, arrow indicates facial horn, second prothoracic spiracle not drawn (b) contour of anterior part laterally, arrow indicates facial horn, (c) prothoracic spiracle, (d) facial horn ventrally, (e) last two segments in dorsal view, (f) head in ventral view, (g) head in anterior view, (h) sternal spatula, (i) eggs from inside of female abdomen.