88 .MR. NEWPORT ON THE ANATOMY AND DEVELOPMENT 
slight median ridge, and a narrow membranous border, admirably fitted with the margins 
of the maxillæ for suction. The strength of the mandibles, and the consolidation of the 
parietes of the entire head, prove to us that the force necessary to overcome the contractile 
power of the tissues in the Sphinx, in obtaining nourishment, is by no means inconsider- 
able; yet this force appears to be little, if at all, under the power of volition, since the | 
Ichneumon-larva, like that of Paniscus, exhibits only the very slightest indications of 
sensation, when touched or pressed. It makes no distinct effort to escape, but merely 
contracts its body, perhaps simply by reflected action, without any intervention of con- 
sciousness. This is precisely the condition, as regards the consensual functions of its 
nervous system, (fig. 9.) under which we might have expected it to exist. Shut up in 
the body of another animal, and subjected to the compression of its tissues, the endow- 
ment of sensation would only entail on it an amount of suffering proportioned to the 
degree of its perception. Vegetative, or simple organic life, therefore, is, as yet, sufficient 
for all the requirements of its existence; although afterwards it is to become endowed, as 
certain of its consensual organs are developed, with perceptions and instincts the most 
acute. Thus we find in this larva that organs of vision, totally useless to it in its intra- 
abdominal abode, do not yet exist; and the place of their future development is scarcely 
even indicated; while the antennæ, almost equally useless to it in its present condition, 
exist only in the most rudimentary state, merely as slight horny elevations, on the front 
of the head, (fig. 5 a) on each side of the clypeus (6), formed of a series of concentric rings 
(fig. 6) the centre of which is the apex of the future tactile organ. Into this centre I 
have succeeded in tracing the termination of the antennal nerve; the optic nerves, for the 
future eyes, being in their usual situation at the sides of the cerebral ganglia. I have 
also succeeded in tracing this nerve into the corresponding part in the larva of Anthophora, 
in which the antenna is more developed than in Ichneumon, and forms a little cone of 
concentric rings. In Monodontomerus the same part is terminated by a single hair (fig. 7), 
precisely as hairs and spines originate in the central nuclei of tegumentary cells in the — 
larva of Meloé. — 3 
I have elsewhere shown* that the form of the digestive apparatus is very similar, at the 
earliest periods of growth, in all parasitic Hymenoptera, whether they are enclosed in the 
same cell with their victim, as in Monodontomerus, whether carried about with it attached 
to its surface like Paniscus, or whether shut up within its body like Ichnewmon. In each 
of these instances there is not merely a general similarity in the form of its parts, but 
there is also a concordance in their function. The intestinal portions continue small and 
imperfect, and no fæces are passed until the larva has arrived at its maturity. I may now 
further state that this principle, or law, is not confined to the strictly parasitic, or carni- 
vorous larvee, but operates, as I believe, among the omnivorous, and certainly among the 
true pollinivorous. The digestive apparatus in the larva of Zchneumon (fig. 8), is a pear- 
nu à ER > sgh cem only 2 zn short intestine (y, A, à), through which, I have 
from the great digestive or icm H e seth sea lemmings Mee 
with its length. Hence we might expect tend noe 2.1 larger diameter as compared 
E" . might expect to find but little variation in its function. In 
: . * Linnean Transactions, vol. xxi. p. 61. 
