1878. ] Extrication of Silkworm Moths. 381 
On examining two dry denuded specimens of A. /una, the 
black spine was seen at the base of each fore wing, and external to 
but opposite the end of each patagium. The spine, which may 
be called the sector coconis, is figured by Mr. J. S. Kingsley in the 
accompanying cut. A represents the specimen of A. /una which 
came out of the cocoon and died 
with the wings not expanded. It 4 * 
represents a front view of the moth 
3 with the shoulders elevated and the 
y rudimentary wings hanging down; 
s, the cocoon-cutter ; p, patagium. 
B represents another specimen with , 
fully developed wings; ms, scutum; 
st, scutellum of the mersikondt 
segment; s, the ` cocoon-cutter, 
which is evidently a modification of 
one of the pieces at the base of the fore wings; it is surrounded 
: by membrane, allowing free movement. C and D are different 
i views of the spine considerably magnified, showing the five or six 
irregular teeth on the cutting edge, the spine being sharp, curved 
and conical. It will be seen that it acts like a rude saw. 
A e ee oP ae se hy 
Cocoon cutter of the Zuna moth. 
A number of other members of the sub-family Atéaci were 
examined, and this cocoon-cutter was found to be present in all. 
In Zelea polyphemus it is large and well developed, though 
according to Mr. Trouvelot the moth does not apparently need it; 
still, fresh observations directed to this point may show that it is 
put to active use. In Callosamia promethea, Platysamia cecropia, 
and P. gloverit it is rather small. Its use in this latter genus, 
where the cocoon is left ‘partly open at one end does not seem — 
necessary, still it may come in play while the moth is pushing — 
through the threads which it first encounters. In Samia cynthia, 
and an Attacus from Nicaragua, and Attacus amazonia Pack, 
from Pebas, Peru, the cocoon-cutters are rather small, about one- 
half as large in proportion as in A. /una, yet the spines are black. 
Ae Ei a iS T e 
It is large and well marked in the European Saturnia ee ee, 
minor and Endromis versicolora Linn. 2 
In Bombyx mori the spines are not well marked, and they are 
points,.being acute angles of the .pieces at the base of the wing. r 
Their ors need ceme in alcoholic — via we 
quite different from those in the Aztaci. There are three sharp o 
