TACHINIDAE OF AUSTRALIA Il 
bend of vein M. The forward curvature or angulation of the median vein (1) 
where the bifurcation of WM, and M, occurs, or if there is no bifurcation then 
the part of M where a forward change in its general direction occurs before it 
attains the wing margin (cuwbitulus) (Text-figs 10 & 11). 
The nature of the bend can be of great taxonomic importance (e.g. in 
differentiating the Blondeliini with an open gently curving bend from the 
Exoristini with a sharply angulate bend). A few Tachinidae lack the apical 
part of the vein (i.e. M,) and there is therefore no bend, and some very rare 
aberrant forms have only a very slight forward inclination of M. 
cell R;. The wing cell distal to cross-vein v-m and enclosed by vein R,. , anteriorly 
and veins M and M, posteriorly (apical cell) (Text-figs 10 & 11). 
An important taxonomic character is provided by this cell and its associated 
venation according to whether it is ‘open’ or ‘closed’. If the veins R4,,; and 
M, reach the wing margin separately from each other then cell R; reaches to 
the wing edge (Text-fig. 10) and is open; but when veins R,,, and M, coalesce 
and form a short common stalk (‘petiole’) before reaching the wing margin the 
cell is isolated from the edge of the wing and is closed (Text-fig. 11). In the 
latter case the cell is described as ‘petiolate’ (prefixed ‘long-’ or ‘short-’ if 
desirable). Intermediate forms occur in which the cell is closed just at the wing 
margin. 
The cell is open in the vast majority of Goniinae, Tachininae and Proseninae, 
but is commonly closed and long-petiolate in Phasiinae (e.g. <Alophora, 
Cylindromyia, Leucostoma, Euthera). 
cerci. The inner median pair of articulated processes attached to the epandrium 
of the male hypopygium (mesolobes, inner forceps, anal forceps) (Text-fig. 21). 
Conformation and degree of fusion of the cerci have some taxonomic importance, 
but relatively little at supraspecific level. 
costa. The strong vein forming the fore margin of the wing. 
costal sector. A segment of the costal length between any two successive veins 
that end at the costa. 
costal spine. A short strong seta on the costa at the apex of vein Sc, inserted 
immediately before the costal ‘break’. 
Usually undeveloped or very inconspicuous, if strong then normally not 
exceeding v-m in length. Taxonomic value mainly at specific level. 
cross-vein m-cu. The most distal wing vein connecting veins (7 and Cu, (posterior 
cross-vein, hind cross-vein, m-m, M,) (Text-figs 10 & II). 
The position at. which m-cu joins M (whether mid-way between 7-m and the 
bend or nearer to the latter than the former) and the obliqueness of the vein 
have some taxonomic importance (e.g. in Voriini the cross-vein is exceptionally 
oblique in relation to the long veins and the wing in this tribe has a distinctive 
appearance on this account). 
cross-vein r-m. The very short length of vein connecting veins R,,, and M/, and 
closing cell R, at its base (anterior cross-vein, R6) (Text-fig. 10). 
In itself of no taxonomic use but a reference point for determining length 
proportions on the long veins. 
