16 R. W. CROSSKEY 



lower calypter. The larger ventral one of the pair of membranous lobes at the 

 wing base rigidly attached at its base to the suprasquamal ridge (squama, 

 thoracic squama, Thorakalschuppchen of Mesnil). 



Taxonomic characters of the lower calypter lie in its shape and vestiture, 

 and at specific level in colour. It is well developed in all Tachinidae, and in 

 some is grossly enlarged (e.g. in an undescribed Leucostomatine from 

 Madagascar the lower calyptrae of the male are so enormous that they completely 

 hide the abdomen). In some forms (e.g. Palpostomatini) the lower calypter is 

 subcircular posteriorly and diverges from the scutellum but in many it is very 

 broad posteriorly and its inner edge abuts close to the scutellum (e.g. Sturmiini 

 and many other Goniinae, many Phasiini). In a few Goniinae (Ethillini, some 

 Winthemiini, some Carcelia) the outer edge of the lower calypter is bent abruptly 

 downwards. Normally the upper surface is bare but fine erect hairing is present 

 in a few forms and provides a useful key character (e.g. Nemoraea, some Senostoma, 

 some Rutilia (Chrysorutilia)). 



lunula. The crescentic sclerite between the antennal bases and the frons (frontal 

 lunule) (Text-fig. 2). 



Useful as a descriptive landmark, but otherwise of little value. Bare in all 

 Tachinidae. 



marginal scutellar setae. The strong setae around the edge of the scutellum 

 collectively. 



The total number of pairs of these setae can provide a useful key character. 

 In a few forms the marginal setae are more numerous than usual, slightly or 

 strongly spiniform, and not clearly differentiated into basals, laterals and 

 subapicals (e.g. Formosia, Rutilia). 



median marginal setae. Setae standing on the middle part of the hind margin 

 of an abdominal tergite (the MM of Townsend) . 



mediotergite. The posterodorsal declivity of the thorax below the postscutellum 

 and between the halteres (lateral postscutellar plates -f- basiscutellum of Townsend) 

 (Text-fig. 7). 



Not used in taxonomy except for presence or absence of fine hairs on the 

 mediotergite near the base of the lower calypter (infrasquamal hairs, q.v.). 

 Shape might have taxonomic value but has been insufficiently investigated. 

 In some forms the middle part immediately ventral to the postscutellum (i.e. 

 the basiscutellum of Townsend) is differentiated by a distinct line on each side 

 from the lateral parts (i.e. the lateral postscutellar plates of Townsend), but in 

 others (e.g. Doleschalla) there is little sign of such differentiation. 



mentum. The sclerotized shaft or main plate of the proboscis (figs 12 & 13 in 

 Crosskey, 1973). 



Length and shape of the mentum of the proboscis have some taxonomic use, 

 e.g. in Rutiliini in which the mentum in some forms seen in profile is distinctly 

 tapering while in others it is parallel-sided. 



mesonotum. The prescutum and scutum together (Text-fig. 4). 



Markings of the mesonotum when present, e.g. vittae or spot-patterns, have 

 some taxonomic usefulness. Strictly, the mesonotum is formed of a scutum 



