TACHINIDAE OF ORIENTAL REGION 57 



- Parafacials bare ............ 22 



22 Fore tarsus of $ conspicuously enlarged and with minute claws, usually strongly 



laterally (sometimes dorsoventrally) flattened. Abdomen more or less laterally 

 compressed (especially on last two visible tergites). [Mostly very slender black- 

 bodied forms with <J eyes usually very closely approximated and vein R x always 

 bare.] MINTHOINI (p. 85) 



- Fore tarsus slender in both sexes. Abdomen with little or no trace of lateral 



compression. [Varied forms, sometimes with broad <J frons and sometimes with 



vein R, setulose] THELAIRINI (p. 74) 



[Note that the genus Metopomintho, which is tentatively assigned to Phyllomyini, 

 will run out here as it has bare parafacials and non-enlarged $ fore tarsus.] 



Tribe PALPOSTOMATINI 



The members of this small tribe attack adult beetles belonging to the Scara- 

 baeoidea. The phyletic affinities of the tribe and the limits of its constituent 

 genera are poorly understood, and a comprehensive revision is much needed. As 

 in most groups of tachinids there are too many ill-defined genera that merge into 

 each other when sufficient material is taken into account: this was already evident 

 to Malloch (1927a : 339) fifty years ago, when he complained in amusing and 

 Philippic fashion against Townsend's needless erection of the genus Pseudopalpostoma. 



Several genera occur in the Oriental region and on this account I have made 

 a careful examination of the external characteristics of the group so as to provide 

 a preliminary basis for more detailed revision at a later stage: the information 

 here provided supplements that already given in an earlier paper dealing with the 

 Australian fauna (Crosskey, 19736). In this earlier work I provided a preliminary 

 diagnosis of the tribe (especially based on its typical members), and suggested that 

 the Oriental genus Eutrixopsis Townsend might not be a true palpostomatine, and 

 (whilst not establishing definite synonymy) suggested that the Oriental genus 

 Hamaxia Walker should be treated as a synonym of Paipostoma Robineau-Desvoidy. 

 It is now possible, from further study during the preparation of this paper, to 

 elaborate upon the points made earlier. 



Firstly, the synonymy of Hamaxia with Paipostoma: up to now these genera 

 (the former Oriental and the latter Australian) have been considered distinct 

 mainly because the wing cell R 5 is open in Hamaxia but closed and short-petiolate 

 in Paipostoma, but in the light of all the shared characteristics this distinction no 

 longer appears tenable for generic separation. One glance at Hamaxia is sufficient 

 to show that it possesses the papilliform processes on the labellae, the two post ia 

 setae, the two pairs of scutellar setae, the bristled prosternum, the head facies, and 

 all the other features of Paipostoma, but that cell R 5 is open instead of closed. 

 But R b , whilst it appears always to be closed in Australian Paipostoma, is not always 

 petiolate, for in some specimens of P. subsessile Malloch from New South Wales 

 the petiole is obsolescent and the cell closed at the wing margin (Malloch's name 

 subsessile refers to the brevity of the petiole). The existence of intermediates 

 between Hamaxia and typical Paipostoma makes it impossible to maintain both 

 genera as valid, and Paipostoma is here redefined so as to include within it the 



