Mitrodetus Gerstaecker

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 : 93-95

Genus Mitrodetus Gerstaecker

Mitrodetus Gerstaecker, 1868: 67 . Type-species, Cepholocera dentitarsis Macquart (orig. des.).

Head in anterior view about one and one-half times as broad as high; face at antennae nearly one-half width of head; oral margin at about one-third distance from lower eye margin to antennae. Proboscis very slender and three to four times length of oral cavity, labella slightly wider than stem (Fig. 7), palpi slender and about one-third length of oral cavity. Antennal segment 1 cylindrical and about four times as long as broad; 2 about one-fourth length of 1 and about as broad as long; 3 cylindrical and from one-half to two-thirds as long as 1; club slightly longer than 1-2, about one-third as wide as long at twothirds its length, usually collapsed and distorted so that its form is uncertain (Fig. 21).

Mesonotum de11se semierect to erect pilose and with only the narrow intermediate stripes bare at times, lateral margins and humeri at times with very dense recumbent hairs directed outward; bare of pollen, varying to the lateral margins, dorsocentral stripes and central stripes densely pollinose. Scutellum with many long hairs. Postscutellum slightly rugose, with dense clumps of long hairs on lateral slopes. Pleura pilose on episternum-L, pteropleura, katepimeron, and episternum with dense clumps at times on episternum-l and pteropleura; the hairs are long and at times extend over the bare laterotergite.

Abdominal tergite-la nearly flat with dense clump of erect hairs; Ip with quite dense and erect hairs, dense and erect hairs occur on 1 and basal side of 2, 1 and all of 2, 1 and,all of 3, and 1 and all of 4; remaining hairs fairly long and semierect in males, almost bare in females except for short, erect hairs on 8; bullae (Fig. 49) large, three to four times as long as broad in males and about two times as long as broad in females. Male sternites 1-4 with long and erect hairs, sparse to dense, usually dense on 5-8 but short or long; sternite 8 hidden to nearly as long as 7, which is short; female sternites 1-2 with very sparse and long hairs, 3-7 practically bare of hairs, 8 with short retrorse hairs, with circlet of strong spines. The male genitalia (Figs. 96-98) has been illustrated and described by Karl (1959: 670-671, fig. 50), as follows:

"The hypopygium of this species is not rotated around the longitudinal axis of the abdomen and the eighth segment of the abdomen is fully preserved. The genital complex is dorsally bent, and as in the asilid Erax aeetuans, the gonopods effect this "backward arching". The two halves of the epandrium are still connected basally. The hypandrium is no longer to be detected as an independent sclerite. It is much more probable that it is coalesced with the gonopods, as in the asilid Obeiophorus landbecki , rather than reduced, as in Laphria and other asilids".

"It may be mentioned that not only certain Asilidae (Obelophorus) , but also several Rhagionidae (Chrysopil'll8) Symphoromyia ), have a hypandrium rather strongly coalesced with the basistyli".

"The gonopods are also very apomorphic, in that they are bent up and especially, no longer posses a dististylus. The absence of a dististylus I have elsewhere noted only in the asilid Atomosia dispar . Each basistylus is distally divided. Dorsally (under the epandrium) the gonopods are connected by a bridge-like sclerite, which is also coalesced with the aedeagus".

"The aedeagus is short and bulky, as well as drawn out at the sides like a wing, its opening relatively large. 'Cross-apodemes' are present as in the Dasypogoninae and Leptogastrini . The ejaculatory apodeme has considerable size. The cerci show their original character, in that they are not coalesced with each other; they surround the anal papilla together with the ventral lamella".

Legs slender; hind femora about eight times as long as wide, venter with about 15 sharp spines and a rather dense fringe of long, erect hairs. Hind tibiae cylindrical, with three or more long apical bristles. Hind metatarsus about five times as long as broad and as long or longer than segments 2-4.

Alulae with a fringe of short fine hairs. Wings about three times as long as broad; veins M1 and M2 separate, vein M1 ending in R1 so first posterior cell is closed, vein M~ usually ending in costa so second posterior cell is usually open; the veins forming the second submarginal cell frequently coalesced before they reach R 1 but usually they are separated; posterior crossvein absent; ambient vein very weak; axillary lobe about one and one-half times as long as wide (Fig. 71).

Length, 11-19 mm.

Geographic range: Chile, Argentina.