TACHINIDAE OF AUSTRALIA 55 



Propleuron haired EUSTACOMYIA Malloch 



Wing with cell R b open to the wing margin and bend of vein M sharp and provided 



with a definite short M, appendix APALPOSTOMA Malloch 



Wing with cell i? 5 closed at or before the wing margin (usually short petiolate) and 



bend of vein M without trace of appendix . PALPO STOMA Robineau-Desvoidy 



[The extralimital genera Hamaxia and Hamaxiomima differ from Palpostoma 

 only in having cell i? 5 narrowly open at the wing margin, like Apalpostoma. The 

 closure of cell i? 5 probably should not be considered sufficient for generic separa- 

 tion and Hamaxia and Hamaxiomima would be best placed as synonyms of 

 Palpostoma on a redefined basis. Similarly Apalpostoma should probably be 

 merged with Palpostoma if the presence of a short M 2 appendix at the bend of 

 M is the only remaining distinction] 



Tribe MYIOTRIXINI 



Townsend (1936) erected this tribe for the single genus Myiotrixa Brauer & 

 Bergenstamm. This -is a very aberrant tachinid that is still known only from the 

 male holotype of M. prosopina in the Vienna Museum. The affinities of this species 

 are very obscure and it is therefore appropriate to retain it in its own tribe until 

 its relationships can be determined. The general appearance of the head with 

 its very reduced antennae, lack of vibrissae and broadly dilated flattened setulose 

 facialia is reminiscent of certain ormiines or ormiine-like forms and there may be 

 some relationship between Myiotrixa and these forms, or perhaps with the 

 Palpostomatini; any suggestions on the affinities are mere guesswork, however, 

 in the absence of any knowledge of the female, the early stages or the host relations 

 (the overall appearance conveys the impression that Myiotrixa might parasitize 

 beetles but there is no evidence for this at present) ; possibly the Myiotrixini should 

 be placed in Proseninae. 



As Myiotrixa has been rather poorly described up to now, and not previously 

 figured, the opportunity is here taken to provide a figure (Text-fig. 40) of the curious 

 head and a description of the principal characters shown by the type-specimen 

 (the thorax of the holotype is badly damaged where it is pierced by the large 

 mounting pin but the specimen is otherwise in fair condition and most of the 

 characters can be made out without difficulty: it appears that the specimen was 

 still rather teneral when collected as the lunula and antennal bases are still partially 

 retracted). 



Head profile as in Text-fig. 40; eyes rather strongly oblique, with very short sparse hairing; 

 vertex about twice as wide as the antennae, slightly sunken around the ocellar triangle; ocelli 

 present, ocellar setae absent; head drawn down anteroventrally so that in profile it forms 

 a rather sharp angle at the epistomal margin; epistome completely invisible in profile, 

 completely flat and equibroad with the face, very sharply differentiated from facialia; facial 

 ridges evanescent above but expanded and flattened below and reaching to anteroventral 

 corners of the head; genal dilation well developed, obliquely reaching to anteroventral corner 

 of the head; gena about one-fifth of eye height; parafacials very narrow, at mid point much 

 narrower than the antennae; interfrontal area well developed, about twice as wide as a 

 parafrontal. Inner vertical setae convergent, outer vertical setae present and strong; frontal 

 setae in about eight pairs, inclinate and crossed, rows not reaching much below level of the 

 lunula; two pairs of long fine erect orbital setae that are scarcely differentiated from the 



