54 R. W. CROSSKEY 



difficulty is, however, that if such groups of tribes are merged the enlarged tribes 

 become even more difficult to define and almost impossible to key out satisfactorily 

 on external adult morphology (upon which all keys must depend when dealing 

 with a little worked fauna like that of the Oriental Region) - and even in the 

 restricted sense the tribes of Tachininae are excessively difficult to cope with 

 satisfactorily in identification keys. The characters of the various tribes often 

 overlap, chaetotactic characters are frequently unstable, and many forms show 

 gross apomorphic (or presumably apomorphic) changes away from the 'norm' that 

 produce aberrancy of a kind difficult to cater for if keys are to remain at all practical. 

 These facts need to be borne in mind when using the tribal key that is given here, 

 for there is no doubt that it will be difficult to identify every specimen reliably 

 to tribe without some experience. A few aberrant or tribally unplaceable genera 

 have intentionally been left out of consideration when constructing the key in 

 order not to over-complicate it, but the effect of this on the usefulness of the key 

 will be negligible as the forms involved are very rare and not likely to be at hand 

 for naming. 



Key to Oriental Tribes of TACHININAE 



[Note. Special attention is drawn to the points discussed in the paragraphs immediately 

 preceding this key.] 



i Prosternal region of the thorax strongly inflated, ballooning out so that it is easily 



visible in profile ......... ORMIINI (p. 62) 



- Prosternal region of the thorax normal, not visible in profile .... 2 



2 Lower calypter extremely small, not projecting beyond the upper calypter (as in 



Scathophagidae) OXYPHYLLOMYIINI (p. 94) 



- Lower calypter of normal large size but of varied shape, projecting far beyond the 



upper calypter ............ 3 



3 Arista inserted on the apex of the third antennal segment (Text-fig. 50). Antennal 



axis level with the top of the eye or even slightly above it, the frons therefore 

 horizontal or almost so (Text-fig. 50) . Antennae exceptionally long (third segment 

 11-17 times as long as the very small second segment) and with the third segment 

 deeply trifid in the q* (Text-fig. 50) . Genus Trischidocera Villeneuve (? tribe) 



- Arista inserted at or near the base of the third antennal segment (very rarely about 



halfway along its length). Antennal axis below the level of the top of the eye, the 

 frons therefore sloping at least slightly downwards. Antennae normal (third 

 segment not more than seven times as long as the second segment) and with the 

 third segment undivided in both sexes ....... 4 



4 Hind coxa entirely bare on the posterodorsal surface ..... 5 



- Hind coxa with fine soft hair on the posterodorsal surface . . TACHININI (p. 102) 



5 Thoracic surface microrugose. Abdominal vestiture composed solely of short hairing 



without differentiated setae. Presutural seta absent. No intra-alar setae 



GERMARIOCHAETINI (p. 80) 



- Thoracic surface normal. Abdominal vestiture composed of hairing and setae 



(latter sometimes very fine). Presutural seta present. At least one and usually 



at least two intra-alar setae ......... 6 



6 Ocellar setae reclinate. Facial ridge with strong setae on the whole of its height 



(Text-fig. 61). Propleuron haired . . . CAMPYLOCHETINI (p. 65) 



- Ocellar setae proclinate or absent. Facial ridge bare or with weak setae on not 



more than half of its height. Propleuron nearly always bare .... 7 



