56 R. W. CROSSKEY 
in the New Hebrides and Lord Howe Island (whose specific identities are doubtful 
at present) probably also reached these locales from Australia itself. 
The subgenus is perhaps better characterized than the other subgenera and there 
is usually no difficulty in deciding whether any described species does or does not 
fit into Chrysorutilia. The subgenus includes all the Rutilia species that have bright 
yellow heads and hairy parafacials, and it is a useful rule-of-thumb that specimens 
showing these characteristics in combination must belong to species of Chrysorutilia; 
however, there are a few species which evidently belong in this subgenus in which 
the head is not bright yellow (even formosa, the type-species, has the head colour 
slightly brownish rather than yellow) and a few very curious forms from the Philip- 
pines in which the body is entirely blackish brown (atrox Enderlein) or in which the 
parafrontals are bare and brilliant metallic green or blue (Juzona Enderlein and 
splendida Townsend). These Philippine species are discussed further below, as 
two of them are type-species of generic names which are here treated as synonyms of 
Chrysorutilia. 
The characteristics which separate Chrysorutilia from Donovanius and Amenta- 
mima are discussed in the treatments of these subgenera and need not be detailed 
here, but some unusual features of Chrysorutilia are worthy of special note. A 
curious character of the subgenus is the unusually long and conspicuous hair to be 
found on the membranous areas of the prosternal region, and anteriorly on the edge 
of the prosternal plate itself; hair on the membrane occurs in many Donovanius 
species and occasionally in Grapholostylum, but in these subgenera is usually sparse 
and not very obvious, while they never have hair actually on the edge of the proster- 
num, whereas in Chrysorutilia both membrane and plate bear hair and that on the 
membrane is sometimes strong and black and immediately obvious (providing the 
head of the specimen is set forward sufficiently clear of the lower thorax). Prosternal 
membrane hair of this strong black type occurs on the types of Idania atrox (type of 
Idania) and Philippoformosia splendida Townsend (type of Philippoformosia), and 
conformity of this character (as well as other essential features) suggests that these 
Philippine species should be treated as consubgeneric with typical Chrysorutilia; 
hence Idania and Philippoformosia are here placed as new synonyms of Chryso- ~ 
rutilia. 
Idama and Philippoformosia agree, too, with Chrysorutilia in other essential 
features of the subgenus such as the rounded non-sulcate last abdominal tergite, 
the haired area of the pteropleuron extending well forwards of the posterior sterno- 
pleural seta, the weak development of humeral setae (only two setae on the outer 
half of the callus), the total lack of posthumeral setae, the extremely well developed 
hind tibial fringe, the very bushy tuft of rather long crinkly hair on the suprasquamal 
ridge, and the presence of distinct preapical setae on the scutellum just in front of the 
marginals. However, there are some obvious minor differences between the 
Philippine species and typical Chrysorutilia and they are here placed in separate 
species-groups from the main bulk of the species; the groups are keyed out and 
defined immediately after this discussion section. 
Hairing of the suprasquamal ridge is developed to its greatest extent among the 
Rutiliini in this subgenus. In all Chrysorutilia species the hair of the ridge is very 
