REVISIONARY CLASSIFICATION OF RUTILIINI 39 
the same differences also distinguish Formodexia from Rutilodexia. Formodexia 
resembles Rutilia in having the apical scutellar setae at a lower level than the other 
marginal setae, but is easily separated from all Rutilia species by the hairy postalar 
wall and from almost all Rutilia by having the suprasquamal ridge bare. 
There is a strong superficial resemblance between Formodexia and Prodiaphania, 
especially because of the explanate costal bases of both sexes in both genera and 
because of the strongly narrowed buccal opening, but Formodexia is very easily 
distinguished from Prodiaphania by the exceedingly long slender palpi (palpi ex- 
tremely reduced in Prodiaphania), by the haired postalar wall (postalar wall bare in 
Prodiaphania), by the pubescent arista (arista plumose in Prodiaphania) and by the 
normal small upper calypter (upper calypter much enlarged in Prodiaphania). 
Although Formodexia is unlikely to be confused with the remaining Rutiliine 
genera it may be useful to note the following distinctions: the new genus differs from 
Chrysopasta by having the postalar wall haired and the suprasquamal ridge bare and 
in the bare parafacials, and the same features of the postalar wall and the supra- 
squamal ridge distinguish it also from Amphibolia (but some species of the latter 
agree with Formodexia in having bare parafacials). From Chetogaster, which only 
doubtfully belongs to the Rutiliini, it may be separated at once by the five setae on 
the postalar callus (only two such setae in Chetogaster). 
Additional features of Formodexia to those cited in the diagnosis, given to facilitate 
comparison with various subgenera of Rutilia and Formosia, are as follows: no 
development of strong spiniform setae on either thorax or abdomen; setae of pre- 
scutum and scutum reduced, post ia setae absent; two sternopleural setae (1 + 1); 
_ claws of unusually small; 2 without proclinate orbital setae; hind tibia with short 
well developed and close-set ad fringe; head of $ appearing unusually small in 
' relation to body size; both sexes with a row of well developed setae along the basal 
| half of the a surface of the mid femur. 
_ Asurprising aspect of Formodexia is the extreme paucity of material so far known 
of volucelloides, the only species: I know of only five specimens, all in the British 
Museum (Natural History), of which three are Walker’s types of three synonymic 
names and the other two are old specimens from Batjan that formed part of Bigot’s 
collection. Of the five specimens, only the primary type (lectotype herein desig- 
nated) of volucelloides is a male, but the species is so distinctive that there is no doubt 
_ whatever that the four female specimens are conspecific with this male; as a conse- 
quence, Walker’s names ¢tvixoides and ignobilis fall as new synonyms of volucelloides. 
Enderlein (1936), without seeing Walker’s types and therefore without any real 
idea of their characters, assigned ignobilis to Chrysorutilia Townsend and assigned 
_ volucellordes and trixoides to his genus Donovanius, thus in effect associating these 
names with Rutilia (for Chrysorutilia and Donovanius are, in the present treatment, 
regarded as not generically distinguishable from Rutilia). As already shown, all 
_ three specific names belong to one species which is not assignable to Rutilia. 
' Attention may usefully be drawn here to an error in Walker’s citation of type- 
locality for ignobilis: this was originally recorded in error as Gorrite (in Brazil), 
but the correct type-locality (as indicated by a label on the specimen in Walker’s 
_ writing) is southern Gilolo (= Halmahera) in the Molucca islands. 

