REVISIONARY CLASSIFICATION OF RUTILIINI IL 
ordinarily reduced or absent in females; when present in females their size and num- 
ber often vary, and may be different on each side of the same specimen, but never- 
theless there is a tendency for their normal presence or absence in different segre- 
gates. The vibyissae are sometimes long and strong but most often are weakly 
differentiated from the peristomal setae and from the small setulae above the main 
vibrissae (Text-fig. 3); they have no real taxonomic use. The facial ridges are bare, 
but in Chrysopasta small setulae extend up them further from the main vibrissae 
than is usual. The row of postocular setulae varies somewhat in length and might, 
if sufficiently studied, show minor specific differences in males. 
Thoracic chaetotaxy (Text-fig. 9). The most valuable chaetotactic characters are 
on the thorax, and several groups of thoracic setae provide generic and subgeneric 
characters. The basic number of humeral setae is four, two on the outer half and 
two on the inner half of the humeral callus, but in some Rutilia s.l. the inner pair is 
absent or virtually-so. The posthumeral setae (pf) are typically developed in some 
genus-group segregates and undeveloped in others but are of very minor taxonomic 
usefulness; often their development is variable, and in males ph setae may be un- 
differentiated from the prescutal hair although distinct in females. The acy and dc 
setae are especially variable and almost no use has been made of them in the present 
work; in Formosia the presence of a distinct prst dc seta in one group and not in 
others has been noted. Some segregates characteristically show some strong slightly 
spiniform setae on the scutum between the hindmost setae of the acy and dc rows 
(so that the scutum shows a rather continuous transverse row of strong setae imme- 
diately before the scutellum); the presence or absence of these supernumerary 
prescutellay setae provides a minor taxonomic character. The pre-alar and supra- 
alar setae are extremely variable in development and have no taxonomic value; 
the pra seta may be present or absent in the same species or on the two sides of the 
same specimen, and there may be several supra-alar setae or only one in the same 
species. The notopleural setae are normal (1 + I) in almost all forms, but a few 
curious species from the Philippines have a well developed third notopleural seta 
standing very close to the normal posterior notopleural (i.e. I + 2 notopleurals), 
the hind pair standing on an unusually prominent knob-like swelling of the noto- 
pleuron. Intra-alar setae occur only as post 1a setae on the scutum, and there is 
never a prst ia seta in Rutiliini, but the post za are often intraspecifically variable; 
typically in any species there may be only one post ia, but almost always occasional 
specimens will be found in which a second or even third fost ia is present, and in 
species in which there is normally more than one there may sometimes be found 
only a single post ia; consequently the za setae have very limited taxonomic value. 
The most dependable thoracic setae for taxonomic purposes are the postalar setae 
on the postalar callus, the sternopleural setae, and the scutellar setae. Omitting 
Chetogaster (which has two postalars like normal Tachinidae) the Rutiliini are very 
exceptional in having more than the basic two setae developed on the postalar 
callus, there being either three very strong setae or four or five (exceptional speci- 
mens may even have six, with or without a weakly developed seventh seta). The 
possession of either three postalars or more than three appears without doubt to 
aggregate Rutiliine species into natural groupings, though the development of one 
