Messiasia d' Andretta

J. Wilcox & N. Papavero, 1971, The American Genera of Mydidae (Diptera), with the Description of three new Genera and two new Species, Arquivos de Zoologia 21 (2), pp. 41-119 : 88-91

Genus Messiasia d' Andretta

Messiasia d'Andretta, 1951: 52 . Type-species, carrerai d'Andretta (orig. des.).

Head in anterior view one and one-half times as broad as high; face at the antennae about three-eights width of head; oral margin at about two-fifths distance from lower eye margin to antennae. Stem of proboscis about one-half length of oral cavity and attached to middle of labella; labella semicircular and subequal to length of oral cavity; palpi short, about as broad as long. Antennal segment 1 cylindrical and one and one-half times as long as wide; 2 about one-third the length of 1 and slightly wider than long; 3 slender and about three times as long as 1-2; club subequal in length to 3, at two-thirds length about one-third as wide as long (Figs. 17-19).

Mesonotum bare of pollen, hairs short recumbent. Scutellum with short, sparse, marginal hairs. Postscutellum rugose, bare. Pleura pilose on episternum-1, pteropleura, and metasternum.

Abdominal tergite-1a slightly rounded, bare; 1p with quite dense, erect hairs; remaining segments with quite numerous, recumbent hairs; bullae (Fig. 47) about five times as long as wide. Sternites with sparse recumbent hairs becoming numerous on 7-8; 0' 8 one-fourth length of 7 and with longer hairs. Female terminalia with apical hairs, tergite 8 with an apical semicircular membranous area (Fig. 60). Male genitalia (Figs. 85-87): hypandrium completely coalesced with basistyli, resulting structure roughly hemispherical in most species, subrectangular in Messiasia notospila (Wiedemann) , but always in the form of a more or less cupshaped capsule; apical processes of the gonopod short and thick, triangular, pointed inwards; in Messiasia decor (Osten Sacken) the apical processes are longer and more slender; the aedeagus is a conical tube, and in Messiasia decor (Osten Sacken) the lateral apodemes are strongly developed, and dorsally bent (see d'Andretta, 1951: figs. 177-183, p. 61); epandrial halves triangular in all known species (Figs. 88-92), differing in this from the majority of the species of Mydas Fabricius , where the epandrial halves are subtrapezoidal; in Messiasia the epandrial halves are fused basally for a short distance; cerci united at base. The genitalia of the several species of Messiasia have been figured byd'Andretta (1951: pl. 13, p. 49; pl. 14, p. 53; pl. 15, p. 57; pI. 16, p. 61).

Fore and middle legs slender. Hind femora quite strongly to moderately swollen, varying from about four to seven times as long as broad; venter with about 16 short, tuberculate spines; hairs variable but usually some long erect ones on dorsum. Hind tibiae with ventral keel, apex with a spur which is not quite as long as the width- of the metatarsus. Hind metatarsus about three times as long as wide and subequal in length to segments 2-3.

Alulae with dense fringe of squamose hairs. Wings about two and one-half times as long as broad; second submarginal cell and first posterior cell open; posterior crossvein present; axillary lobe as broad as long; ambient vein complete.

Length, 15-29 mm.

Geographic range: U. S.A. (Arizona and California) South America (but not reported from Chile).

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southern