io R. W. CROSSKEY 



The height of the axis relative to the eye centre and the head length at this 



axis in relation to head length at the epistomal axis can be significant in 



describing head form. 

 apical scutellar setae. The hindmost pair of marginal setae on the scutellum 



(except when undeveloped) (Text-figs 5 & 6) . 

 Orientation of these setae (whether horizontal or upright, crossing or 



diverging) can be taxonomically important. If the apical setae are unrepresented 



then other marginal setae are the hindmost ones in a literal sense. 

 appendiculate. Provided with an M 2 appendix (q. v.) (said of vein M) . 

 appendix. A spur-like vein of varied length that continues almost directly towards 



the wing margin from the bend of vein M (designated M 2 ) (Text-fig. 10). 



Normally present only when vein M is abruptly angled and sometimes 



represented only by a weak vestige or even a mere fold in the wing membrane. 

 arista. The setiform or style-like part of the antenna arising externally from 



the base of the third antennal segment (German: Fiihlerborste) (Text -fig. 1). 

 Present in all Tachinidae and providing useful taxonomic features in hair 



length, extent of thickening, and elongation of the two basal segments. 



Typically it is micropubescent (with very inconspicuous hairing that is shorter 



than its own diameter) or pubescent (with more conspicuous longer hair that 



does not or only slightly exceeds its own diameter), but may be plumose (with 



long hairs that greatly exceed in length its own diameter and give the arista 



an obvious bushiness). Micropubescent or pubescent in all Phasiinae and 



nearly all Goniinae, often plumose in Proseninae and Tachininae (especially 



Minthoini). 

 barette. A small subrectangular area on the pleural region of the thorax 



differentiated between the pteropleuron and the hypopleuron (meropleuron) 



(Text-fig. 7). 



Of minor taxonomic importance in the extent of its hairing. Usually a few 



hairs only on anterior part but commonly bare, less often fully haired along 



its length (e.g. in most Rutiliini, Winthemia). 

 basal node of R 4 + 5 . The slightly or strongly swollen basal part of wing vein 



R i+5 near its bifurcation from vein R 2 + a (Text-fig. 10). 

 Usually bearing one more more small hairs or setulae on the upper surface 



(usually also on lower surface), sometimes totally bare (e.g. in many Phasiini, 



a few Blondeliini and Leskiini). Presence of only one very strong setula (e.g. 



in Palexorista and allied Sturmiini, many Neaerini and Acemyini) in contrast 



to several small hairs is often taxonomically important. 

 basal scutellar setae. The pair of marginal setae nearest to the scutellar base 



(except when, very rarely, undeveloped) (Text-figs 5 & 6). 

 The most constantly present pair of scutellar marginal setae throughout the 



Tachinidae, unrepresented in a very few forms (e.g. some Minthoini). 

 basicosta. The small sclerite anteriorly at the wing base between the tegula 



and the base of the costa (subepaulet) . 



The colour (whether clear yellow or orange instead of blackish brown) of this 



sclerite is of minor taxonomic value in different parts of the family. 



