20 R. W. CROSSKEY 
and Tasmania, Moluccas, Timor, Aru Islands, Kai Islands, New Guinea, Solomon 
Islands, New Hebrides, Fiji, Samoa, and Lord Howe Island. Unrecorded from New 
Caledonia, but probably occurring there. Absent from New Zealand. 
Discussion. Since the time of Brauer & Bergenstamm (1889) specialists in the 
Tachinidae have been agreed in regarding the Rutiliines as a named family-group 
segregate distinct from other Proseninae (=Dexiinae of authors), though the group 
has been variously ranked as a tribe, subfamily, or even occasionally as a family, and 
sometimes has even embraced the Ameniines—a curious group of calyptrate flies 
with an astonishing superficial likeness to the Rutiliines but now accepted as a sub- 
family of Calliphoridae (Crosskey, 1965). It is unnecessary here to review all of the 
varying interpretations of status and scope of the group, but the few major works of 
the past 35 years require brief consideration. 
Townsend (1936) treated the one family Tachinidae, as currently accepted, as 
being seven families, of which the Rutiliidae were a small family on their own, placed 
between the Prosenidae and the Tachinidae in Townsend’s narrow sense (Townsend, 
1936 : 20, 150-156; 1938 : 410-427); Townsend’s families are, however, very un- 
satisfactorily defined, and his family key has 84 exits (of which three are to Rutiliidae) 
for the separation of seven families. One of the exits to Rutiliidae in the key © 
(Townsend, 1936 : 8) relates to those Rutiliines which have the suprasquamal ridge _ 
(=tympanic ridge of Townsend) haired, and there is never any problem in distin- 
guishing these forms from all other Tachinidae: but it is much more difficult in 
defining the Rutiliines to take account of the forms which, though obviously Ruti- 
liines also, have the suprasquamal ridge bare—for the characters of the Rutiliines 
as a whole then merge rather imperceptibly with those of the Prosenines (Prosenidae 
of Townsend). For this reason it is impossible to separate the Rutiliines from the _ 
Prosenines so distantly as to rank the groups equally (as Townsend does), and it is — 
much better therefore to treat the Rutiliines as being a subgroup within the Prose- 
nines (Dexiines of authors). 
This view was well expressed by Mesnil (1939), in his general essay on Tachinid 
classification, as he divided the subfamily Dexiinae (Proseninae) into two tribes, — 
Rutiliini and Dexiini (Prosenini), distinguishing the former from the latter by the © 
prominent mouth-margin together with a few other less tangible features. My own — 
view is very much in accord with that of Mesnil (1939), both as regards the affinities 
and ranking of the Rutiliines, and is elaborated in more detail in the following 
discussion (in which I have used the currently accepted names Proseninae and 
Prosenini in place of Dexiinae and Dexiini as used by many authors). 
The vast complex of diverse forms which constitute the subfamily Proseninae is 
exceedingly hard to classify satisfactorily at any level, and almost any constellation 
of characters which appears to be satisfactory for defining a genus-group or family-_ 
group taxon when only a small collection or a limited regional fauna is available 
tends to become almost worthless for taxon definition when a comprehensive collec- 
tion of worldwide forms is studied. Yet so great is the number of forms to be coped 
with that some segregation of family-group categories is needed, even if these are 
difficult to define in a fully satisfactory way and even if some genera are hard to 

