88 MR. NEWPORT ON THE ANATOMY AND DEVELOPMENT 



slight median ridge, and a narrow membranous border, admirably fitted with the margins 

 of the maxilla? 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 antennae, almost equally useless to it in its present condition, 

 exist only in the most rudimentary state, merely as slight homy elevations, on the front 

 of the head, (fig. 5 a) on each side of the clypeus (b), 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 Meloe. 



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 Monodontomerm, whether carried about with it attached 

 to its surface like Paniscus, or whether shut up within its body bike Ichneumon. 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 faeces 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 larvae, but operates, as I believe, among the omnivorous, and certainly among the 

 true pollinivorous. The digestive apparatus in the larva of Ichneumon (fig. 8), is a pear- 

 shaped elongated sac (/), with only a very short intestine (g, h, i), through which, I have 

 reason to believe, no faeces are passed until the larva has ceased to take food. It differs 

 from the great digestive organ in the Hornet chiefly in its larger diameter as compared 

 with its length. Hence we might expect to find but little variation in its function. In 



* Linnean Transactions, vol. xxi. p. CI. 



