TACHINIDAE OF ORIENTAL REGION 63 



Mesnil (1973ft : 1 228-1229) takes a different approach, and recognizes two genera, 

 Therobia with Xystomima as its synonym and Plesiooestras with Therobiopsis and 

 Proxystomima as its synonyms (he does not deal with Ormiominda) . Mesnil 

 distinguishes the genera Therobia and Plesiooestrus on the wing and the head 

 proportions, in the following manner: sixth wing vein extending to the wing margin 

 in Therobia, stopping short of the wing margin in Plesiooestrus; r-m with a brown 

 fleck in Therobia, without such fleck in Plesiooestrus; antennal bases separated in 

 Therobia, almost contiguous in Plesiooestrus; and face differently proportioned in 

 the two genera. 



The characters cited by Mesnil undoubtedly hold true for distinguishing some 

 specimens from others when the whole Therobia- Plesiooestrus complex is examined, 

 but many intermediate specimens exist which so completely bridge the character- 

 break that Mesnil uses that it seems impossible to justify the recognition of 

 Plesiooestrus as a separate genus from Therobia. One specimen may be cited as an 

 example that it would be impossible to place generically on the basis of Mesnil's 

 distinctions: the BMNH collection contains a specimen from Tanzania (tentatively 

 identified by van Emden as bicolor Seguy) in which r-m is much thickened and 

 dark brown (exactly like that of the type-species of Therobia and Xystomima) 

 but in which the sixth vein stops well short of the wing margin and the antennal 

 bases are contiguous. The evidence provided by an examination of all the material 

 of the Therobia- Plesiooestrus complex in the BMNH collection convinces me that 

 it is impossible to find a character or suite of characters that will serve to distinguish 

 more than one genus in the complex, and my earlier view is here maintained that 

 Xystomima, Plesiooestrus, Therobiopsis, Proxystomima and Ormiominda must all 

 be treated as synonyms of Therobia. When this approach is taken the result, it 

 appears to me, is that Therobia takes on the shape of a natural and homogeneous 

 genus (any subdivision of which would be unjustified 'splitting'). 



The genus Therobia much needs revising at the specific level, for it is doubtful 

 whether the many specific names involved in the genus really apply to distinct 

 species. From a general inspection of material of the genus in the BMNH it appears 

 as though the same species might well occur throughout the Old World tropics, 

 although up to now species in different regions have mostly been considered distinct. 

 There are, for instance, no obvious external differences between T. abdominalis 

 (Wiedemann) from the Oriento-Australasian area and T. maculipennis Villeneuve 

 from the Ethiopian Region (as Bezzi, 1928 : 202 was aware when he described 

 punctipennis , a synonym of abdominalis), or between T. albifacies (Villeneuve) 

 from the Ethiopian Region and T. vesiculifera Bezzi (probably = composita (Seguy)) 

 from the Oriento-Australasian area. Revision on a comprehensive basis may well 

 show that such 'species' cannot be maintained (up to now the male genitalia have 

 not been studied). 



Lastly, the following points should be noted concerning Oriental Ormiini. (1) 

 Aulacephala karnyi Malloch. The type has not been located and cannot therefore 

 be compared with that of A. hervei Bequaert, but Bequaert (1929) stated that 

 karnyi 'is undoubtedly the same insect' as hervei, a statement that unquestionably 

 establishes the synonymy (here accepted in the absence of contrary evidence) of 



