DASTPOGONINAB 



ROBBER FLIES OF THE WORLD 



291 



Tribes Thereutrini and Enigmomorphini 



The interesting Australian genera, Thereutria Loew 

 and Metalaphria Ricardo have been assigned a place to 

 themselves, the tribe Thereutrini. Related to the Dasy- 

 pogonini, they are at once recognized by the combina- 

 tion of the closed marginal cell, as in the Laphriinae, 

 and the spine at apex of the anterior tibia, together 

 with the spines on the female acanthophorites. These 

 flies are confined to Australia. I found the first men- 

 tioned genus frequenting the leaves of shrubs in the 

 borders of woods, where sun penetrated to the shrub 

 level; the flies of Metalaphria were common on sand 

 and gravel of stream beds. 



To the tribe Enigmomorphini is assigned a single, pe- 

 culiar fly, Enigmomorpheus Hermann. This fly from 

 Paraguay shows several unusual features: it lacks 

 spine on the apex of the anterior tibia; the marginal 

 cell is closed; the female has stout spines on the acan- 

 thophorites, and the palpus has one segment. Its re- 

 semblance to flies of the Diogmites Loew complex, 

 rather than to Stenopogon Loew adds further com- 

 plication to the matter of its relationship and so, be- 

 cause of its aberrant aspects and peculiarities, it has 

 been set apart. 



KEY TO GENERA OF THEREUTRINI AND ENIGMOMORPHINI 



1. Marginal cell closed. Antenna not with terminal style or 



arista. Palpus of 1 or 2 segments. Anterior tibia with 

 or without spine. Females always with terminal spines 



on acanthophorites 2 



Marginal cell open. Palpus of 2 segments. 



Other Dasypoqoninae 



2. Anterior tibia without spine. Palpus of 1 segment (Tribe 



Enigmomorphini .... Enigmomorpheus Hermann 



Anterior tibia with spine at apex. Palpus of 2 segments 



(Tribe Thereutrini) 3 



The oral bristles cover the whole of the low, facial gib- 

 bosity. Proboscis strongly depressed dorsoventrally at 

 apex. The known species are feebly shining, black 

 flies Thereutria Loew 



The oral bristles are situated in, at most, 2 close-set rows 

 along the epistoma. The proboscis is simple. The known 

 species are pale brown pollinose . Metalaphria. Ricardo 



Genus Enigmomorpheus Hermann 

 Figures 107, 567, 1159, 1168, 1607, 1920, 1990 



Enigmomorpheus Hermann, Nova Acta Acad. Caes. Leop.-Carol., 

 vol. 96, p. 272, 1912. Type of genus: Enigmomorpheus 

 paradoxus Hermann, 1912, by original designation. 



Curious flies of medium size which suggest Diogmites 

 Loew in the presence of stout acanthophorite spines but 

 lack any protibial spine. The marginal cell is closed 

 and there is only a single palpal segment. The male is 

 unknown and hence we do not know if the male termi- 

 nalia are rotate as in Diogmites or not rotate as in Ste- 

 nopogon Loew. Length 13 mm. 



Head, lateral aspect: The length of the head is 

 moderate and the face short. The occiput is convex 

 behind, especially below, and moderately long pilose; 

 near the middle of the occiput there begins a double 

 row of rather stiff, pale bristles of moderate length. 

 Well below the vertex and just above the cervix is a 

 patch of 12 still more stout bristles. The proboscis is 

 directed obliquely forward; it is a little wider and 

 more stout at the base, gently tapered to a rounded 

 apex which bears only a few scattered, short, stout 

 hairs ; medially above, the proboscis is gathered into a 

 thin, dorsal ridge which is rather conspicuous at the 

 base. Palpus prominent, cylindrical and composed of 

 a single segment which bears numerous, long bristles ; 



from a lateral view the possibility will be noted that 

 the basal segment of the palpus became completely 

 fused to the ultimate segment instead of being lost or 

 fused to the base of the head as is common in so many 

 genera. Antenna elongate, longer than the head; the 

 second segment is longer than the first; the length of 

 the third segment is not quite two times the combined 

 length of the basal segments. The third segment is of 

 uniform thickness, tapered to the apex, and bears 14 

 dorsal setae; at the apex this segment bears a short, 

 semifused, dorsal and obliquely open pit with enclosed 

 spine. 



Head, anterior, aspect: The head is exceptionally 

 wide but the face below the antenna is little more than 

 one-fourth the head width and slightly divergent below. 

 The face is micropubescent and without pile, except for 

 numerous, stiff, long hairs on the lower third of the 

 face. Laterally these hairs are directed sharply down- 

 ward but in the middle of the face they are replaced by 

 about 8 rather long, and medially longer, shelflike row 

 of stout bristles. These stout bristles are arranged in 

 a single row and there is a little short, stiff pile imme- 

 diately above them. Laterally the front has a few stiff 

 hairs on each side above the antenna and the ocular 

 margin of the front bears 4 quite stout, black bristles. 

 The vertex is only moderately excavated above and the 

 ocellar protuberance is rather low but bears an anterior 



