o 
whose larve are external feeders. S47 
replaced by straight spines, that is, they have a smooth 
outline, and taper continuously from base to apex. They 
have, however, a joint about 3th of their length from the 
base, the apex looking harder, browner, and more solid, 
and they appear to have a central tube. I need not 
allude to their apparent origin from deep tissues, and the 
skin looking like a thick coating of glass, through which 
they come, as this is, I think, a well-known peculiarity 
of these larvee (as also of many Lycenids). 
But the dorsal set of spines are now double, that is, 
the double row, of which the alternate members were 
wanting in the larva of the first stage, is now complete, 
and they remain so even in the adult larva, though they 
are now merely prominences, and not spines. In the 
second and third stages there are, especially in the tho- 
racic regions round the bases of these spines, very minute 
spines, apparently of a structure very similar to the last 
joint of the spines in first stage. 
The spinneret in this larva is remarkable up till the 
penultimate stage, in being not a pointed organ, but 
flattened out like a fish’s tail, and the silk it disposes on 
the leaves for the larva to walk upon, is not a thread, 
but a very thin ribbon. 
This larva has other very interesting peculiarities, most 
of which are, I imagine, well known. These I need not 
touch on, indeed all I am at present interested to touch 
on is the remarkable disposition and structure of these 
spines in the newly-hatched larva, parallel with nothing I 
know of in any other family than the similar arrange- 
ments in Hriocephala. 
Prof. A. 8. Packard has some excellent observations on 
spines of Limacodids, but on none, so far as I know, that 
quite parallel these in structure; and he does not, I 
think, refer to their disposition in the newly-hatched larva 
as similar to that I find in testudo. 
He figures, however, the young larva of Lithodia 
fasciola, which seems to be very like that of testudo, 
though less well-developed, and for this reason, want of 
sufficient material, and insufficient amplification, appears 
not to have noted any of the points I have here drawn 
attention to. 
Among many figures he gives of Ceratocampid and 
other spines, and similar figures elsewhere, and amongst 
my own observations, there are abundant instances of an 
