15 
plisli colour; ancl it is doubtful whether any British species of Nocture 
in their range of variation show more distinctly the gradation in the 
natural genetic sequence of colour—yellow, orange, red and purple — 
than do X. fulvago (cerago ) and X. aarago. These two species are very 
variable, whilst the other species usually included in the genus 
Xanthia, are, as a rule, not given to much variation either in colour or 
markings. 
Hoporina croceago is well separated from Xanthia, although there 
is a general tendency amongst collectors to include it among the “ Sal¬ 
low ” moths; and this brings me at once to the consideration of the 
real nature of the alliance existing between these latter as represented 
in Xanthia. It appears certain, that whatever definition we may choose to 
make of the Xanthidce and their allies, based on the consideration of such 
genera as Orthosia, Anchocelis, Glcea, &c., and represented by such species 
as suspecta, lota, vaccinii and cerago (fulvago ) in various directions, that 
both croceago and citrago will have to be removed entirely from their 
present location and altogether away from the genus Xanthia, as in¬ 
cluding fuluago and flavago. Thus, speaking broadly, Orthosia, Ancho¬ 
celis, Dyschorista and Glcea are all closely allied in different ways to 
Xanthia ; but the two species in question not only show no true alliance to 
the species with which they are grouped, but little to the genera among 
which they are placed. The pupa of croceago is decidedly not Xanthid. 
The true Xanthias have joale larvae, live in hiding (more or less) in 
trees when young, descending to the ground or hiding in bark when 
older ; and having the peculiar markings and marblings characteristic 
of the larvae of fulvago, vaccinii, lota, &c. 
We, of course, recognise at once the general similarity of the mem¬ 
bers included in Xanthia, and there is no doubt, that this “ general 
similarity ” has led to the genus being constituted as at present; but 
when we come to examine the species more closely, even although we 
still do so superficially, we note that even the arrangement of the 
transverse lines is different in citrago from that in the other species, 
and even in aurago there appears a general tendency in the same direc¬ 
tion. So far as markings go, fuluago, flavago and gilvago are very 
closely alike; aurago has the transverse lines very similar, but, whilst 
in the three former species the elbowed line is lost in the transverse 
fascia, in aurago it becomes distinctly the boundary of the blotch be¬ 
tween it and the subterminal line, and, in the same manner, the com¬ 
paratively indistinct subterminal of the first three are replaced in 
aurago by a very distinct subterminal. This, however, is a minor 
matter, but it sets one thinking, and so struck was I with the dissimilarity 
of the markings of citrago that I appealed to Dr. Chapman about the 
matter. He, at once, sent me drawings of the pupal anal segments of 
a typical Xanthia and of citrago, and whilst the former is almost iden¬ 
tical with Glcea (Cerastis ), the latter bears no resemblance to it whatever, 
and is, in fact, much more like a terminal of Cuspidia (one of the sec¬ 
tions of Acronycta) than anything with which it is usually classed. It 
is not even like those of Tceniocampa, which are much like those of 
Hadena, and very distinct from those of Orthosia (Glcea, Xanthia, etc.). 
I feel satisfied that citrago has no real affinities with Xanthia, and that 
its approximation in colour is due to a common habit at the same time 
of the year, and that this is needed for protection, and is no sign of 
actual close affinity. I have no information about X. aurago, but, 
