Dr. T. A. Chapman on Heterogyna penella. 143 
penella, so doubtless they have alternative hosts, as with 
other of these dipterous parasites. 1 forwarded a small 
supply of them to Mr. Bignell, who attempted to ascer- 
tain their name, with the following results from different 
authorities :—Demoticus plebeius; a Blepharidea near Bb. 
vulgaris; a species of Ceromasia. For aught I know these 
are synonyms. 
The female does not usually place her similar but 
much larger cocoon so conspicuously, and I think even 
makes some attempt to hide it, near the ground, under a 
leaf, &c., nor are so many to be seen, though the larve 
are equally abundant. These also produce the dipterous 
parasites, but I think much less abundantly than the 
males. 
The larva in its short squat form and sluggish habits 
reminds one of those of the Zygenas, and like them 
they have minute stellate skin points. They retain, 
however, simple one-bristled tubercles up to the adult 
stage, and so have none of that angularity and upholstered- 
cushion appearance so characteristic of Zygzenas. 
The prolegs also, though of macro-lepidopterous type, 
are much less fully evolved than in the Zygenas. The 
. circle of crochets is, indeed, quite incomplete on the outer 
aspect, but the hooks extend round the front and back of 
the pad suggesting rather a complete circle damaged on 
one side than the fully evolved foot with single inner 
flange of the Zygenas. The formula of the larval tuber- 
cles seems to be the same as that of the newly-hatched 
Zygena. After the trapezoidals and supra-spiracular, we 
find a subspiracular, placed well below and slightly be- 
hind the spiracle, with three points placed in an equi- 
lateral triangle, of which two, an upper and an anterior, 
carry long hairs (Iv and v), the third, below and behind, 
is merely a point; below this are two others (VI and vit) 
on the same level, half-way between the subspiracular 
and the prolegs (marginal). Of the larger larve the 
general skin surface is closely set with extremely fine 
hair- -points, then there are numerous minute tubercles 
each carrying four to six short, apparently tubular bristles, 
these seem to be quite independent of the ordinary 
tubercles. 
In the newly-hatched Jarva, the subspiracular tuber- 
cles are a posterior one, below but well behind the spira- 
cle, and another rather lower and directly below the 
