44 R. W. CROSSKEY 
propleuron is black haired and in which there is no facial keel, the genera Geraldia, 
Acucera, Platytainia, Hobartia and Anatropomyia coming in this category; the first 
three of these genera have the parafacials covered with strong black hair. This 
complex seems to be uniquely Australian and has no counterpart in the fauna of 
the Oriental Region, but some members closely resemble certain Neotropical forms: 
Anatropomyia, for example, has the same essential characters and very closely 
resembles ‘Theresia’ erecta Aldrich from southern Chile (the generic name for this 
species is placed in inverted commas because the species undoubtedly is wrongly 
placed in Theresia Robineau-Desvoidy but has not yet been reassigned). 
Two genera here placed in the Prosenini were recently placed by Paramonov 
(1968) in the Rutiliini, viz. Ola and Ruya (=Rutilotrixa). These genera (which 
are so similar to each other that separate generic status is only doubtfully warranted) 
have a sharp median facial keel (unlike the carina of Rutiliini or of the Prosena 
group of genera) and an aggregate of characters that better places them in the 
Prosenini rather than the Rutiliini, though they are to some extent intermediate. 
The affinities of Ola and Rutilotrixa are uncertain, but they closely resemble some 
similarly robust Prosenini from the southern Neotropical Region, especially 
Psecacera Bigot. 
The genus Tvichostylum is disjunct from the rest of the Australian Prosenini. 
Its overall facies leaves no doubt at a glance that it belongs in the Billaea Robineau- 
Desvoidy complex of genera (or so-called genera) that are a significant component 
of the prosenine fauna of Africa and Eurasia. The holotype of the type-species 
has the propleura totally bare (in contrast to the haired propleuron of Bullaea 
s.l., Philotrichostylum Townsend, etc.) and the genus is on this account retained 
as valid at present, but apart from the bare propleuron it is scarcely distinguishable 
from certain species of Billaea s.l. that lack a facial carina. 
The genus Heterometopia Macquart is uniquely Australian and may not truly 
belong in the Prosenini (where it is here placed as an interim measure) until its 
characters can be more fully studied and its hosts discovered). It is an aberrant 
genus in respect of its head structure and especially difficult to place at present. 
If not a prosenine then it ought probably to be placed in the Tachininae either 
in the tribe Thelairini or in the tribe Leskiini. A study of the male genitalia would 
probably help in determining its position. 
Kry to AUSTRALIAN GENERA OF PROSENINI 
t Head with a large elongate facial carina separating the antennae, the carina 
convex or flattened on its anterior surface (never forming a sharp ridge) and 
when seen in profile appearing abruptly marked off from the epistome by a 
strong concavity (Text-fig. 27). Palpi very reduced, shorter than or at most 
only as long as the third antennal segment. Two sternopleural setae (except 
in Prosenina with three). Arista plumose. [Mainly slender forms in which 
males have exceptionally spindly legs with attenuate, often sinuous, tibiae] : 2 
— Head without a facial carina or with a rather sharp roof-like median ridge that 
does not clearly separate the antennae and when seen in profile is not marked 
off from the epistome by a definite concavity. Palpi well developed, obviously 

