46 ES Wie Cin O's Sika ¥, 
identical terminalia. Throughout most of the Rutilza s.l. species the male sternite 5 
does not significantly differ from that of other Rutilini, and has a simple bilobed 
form (Text-figs 30 & 31), but in two aggregations of species (here treated as the 
subgenera Grapholostylum and Microrutilia) the sternite is atypical: in Grapholo- 
stylum the sternite has exceptionally pointed outer sides and has a pair of curious 
blunt downwardly directed protuberances near the middle (Text-fig. 33); in 
Microrutilia the sternite is also very prominent in profile when in situ but does not 
have the submedian prominences and has each of the lateral lobes distinctly concave 
on its hind margin (Text-fig. 32). 
The aedeagus in Rutilia s.l. is remarkably constant in structure and the only 
character found in it of any taxonomic use lies in the distiphallus. The distal 
membranous part of the distiphallus is normally shorter than, or at most subequal 
in length to, the sclerotized proximal part (Text-fig. 37), but in the subgenus 
Grapholostylum the distal membranous part of the distiphallus is much longer than 
in other Rutilia and has a slender whip-like form which is about twice as long as the 
sclerotized proximal part of the distiphallus (Text-fig. 38). The form of the cerci 
(mesolobes) does not differ very greatly in Rutilia s.1. species, although some specific 
differences are evident, and the cerci do not provide features of subgeneric value. 
On the other hand the shape of the surstyli (paralobes) differs conspicuously among 
different subgenera, being particularly distinctive in the subgenera Donovanius and 
Chrysorutilia. In Donovanius the surstyli are very enlarged and foliaceous in form 
(Text-figs 66-71) (enabling males of this subgenus to be recognized immediately 
the genitalia are examined), and in Chrysorutilia the surstyli (though varied in 
shape) always come to a fine sharp point at the apex (Text-figs 72-84). Other 
subgenera are less distinctive in genital form among tbeir included species, but they 
all differ trom Donovanius and Chrysorutilia by having differently shaped surstyli 
(i.e. by having neither the enormous foliaceous surstyli like Donovanius nor the 
sharply pointed mucronate surstyli like Chrysorutilia). 
In Rutilia s.l. as a whole it is often difficult, unless a species has a particularly 
unusual form of male hypopygium, to determine the limits of species. Many of the 
apparent species have geuitalia that are identical or nearly identical—for example, 
the many distinctive-looking entities considered to be species in the subgenus 
Donovanius actually differ not at all in their male genitalia, or if there are differences 
they are extremely subtle and of no practical use. Some of the colour characters 
that have been used to separate species, for instance whether the metallic areas of 
the abdomen are in spots or bands, seem to be undependable criteria for they fail to 
correlate very often with differences in male genitalia (particularly in the subgenus 
Chrysorutilia in which some species with very distinctive genitalia show the same or a 
very similar range of variation in colour pattern). Furthermore it seems possible 
that some species are polymorphic in respect of hair colour, so that some apparent 
species with yellow pleural hair may not be actually distinct from those with black 
pleural hair; and it also appears likely that some species may have black pleural 
hair in males but yellow pleural hair in females (similar to the sexual dimorphism in 
pleural hair colour found in some species of the higher Tachinid genus Winthemia 
Robineau-Desvoidy). At the present time no firm conclusions can be drawn on 
