
REVISIONARY CLASSIFICATION OF RUTILIINI 17 
far in the genitalia for taxonomic purposes are the surstylz ; these show great diversity 
of shape, ranging from sharply pointed rather hook-like structures to enormous 
foliaceous lobes. In some groups the surstylus shape may be very constant (e.g. in 
Donovanius) throughout a range of species, but other groups may contain an admix- 
ture of species some of which have surstyli differing only by subtleties of outline and 
others of which have unmistakable surstyli showing some bizarre features. Broadly 
speaking, however, each genus-group segregate tends to show a surstylus shape with 
some common denominator—for example a surstylus always ending in a sharp tip or 
always with a subquadrate form. 
Female postabdomen. This has not been studied in detail, but the examination of 
the postabdomen from representative females of different genera has not suggested 
the existence of good characters of value in supraspecific taxonomy. Detailed 
examination of species within a particular subgenus or genus will almost certainly, 
however, show up some differences that will enable females to be more reliably 
determined than at present. 
KEY TO TRIBES OF THE SUBFAMILY PROSENINAE IN THE 
ORIENTAL AND AUSTRALASIAN REGIONS 
The subfamily Proseninae (=Dexiinae of authors) contains a vast assemblage of 
Tachinidae that occur in all the zoogeographical regions and subregions (except 
New Zealand) and appear to be exclusively parasites of beetles. If certain aberrant 
fringe genera are excepted the Proseninae as a whole has a facies which—in spite of 
great diversity in body shape and the degree of development of a facial carina— 
specialists on Tachinidae can recognize, even if they find it hard to pin down exactly 
what the diagnostic characters of the subfamily really are; certainly the form of the 
maleaedeaigus andits associated structures seems to provide some common denomina- 
tor throughout the group. At present there is no available recent definition of the 
Proseninae, and the welter of world forms to be considered will make it difficult to 
atrive at a satisfactory definition that will work on a world basis. Likewise the 
completely satisfactory delimitation of tribal groupings within the subfamily will not 
be easy, and Townsend’s various tribes in his Manual of Myiology need a thorough 
revision. In these circumstances I am not attempting here to provide a definition 
of the subfamily Proseninae, but I nevertheless think it useful to indicate the tribal 
entities which seem to justify recognition in the fauna of the Oriento—Australasian 
regions (in the area to which the Rutiliini are confined) ; an attempt will be made in a 
later work on the Tachinidae of New Guinea to elaborate complete diagnoses of the 
tribes and of the Proseninae as a whole. 
The three tribes recognized in the Oriental and Australasian fauna are the 
Prosenini, Doleschallini, and Rutiliini, which can be distinguished by the following 
key. 
1 Thorax closed above the hind coxae by a broad sclerotized bridge (as in Cylindro- 
mylini), the hind coxae remote from the abdominal base. Head in profile sub- 
triangular, profrons extraordinarily prominent and lower part of head strongly 
receding, head very much longer at antennal axis than at epistomal axis. No 
