294 



but scarcely from pellucida, in the angle formed by the costal with the 

 terminal edge of the front wing being much less acute, or, in other 

 words, by the interior margin being proportionally longer and the 

 terminal margin proportionally shorter. 



It is quite impossible that I should have bred both distigma and M- 

 color from the same larva, thus manufacturing two species out of one, 

 because not only were the two species bred in distinct cages in 1862-3, 

 but I bred, as already stated, a hicolor in 1861-2, which was a year 

 before I became acquainted with the very remarkable larva of di- 

 stigma.* I am familiar with the larva of D. senatoria, and never saw 

 any of them assume the peculiar sphingide attitude, which the larva 

 of S. distigma invariably assumes in repose, clasping at the same time 

 the under surface of the main rib of the honey-locust leaf with its 

 prolegs, so as to be overshadowed and concealed by the leaflets. The 

 young larva of the allied Ceratocampa i-egalis is said by Dr. Harris 

 " when at rest to bend the fore part of the body sideways, so that the 

 head nearly touches the middle of the side." (Inj. Ins. p. 400.) 

 SpliingicamjM seems to be a beautiful connecting link between Cerato- 

 campa and the sphingide genus Ceratomia, the larva of which last has, 

 like the two former genera, horns on the meso- and meta-thorax. In- 

 deed, until I noticed the antennae of the pupa of Sphingicampa, I was 

 fully persuaded that I had got hold of a new species of Ceratomia. 

 The generic distinction between the imagos of Sphi7igicampa and Dry- 

 ocampa is precisely similar to that between the imagos of Aitacus 

 and Saturnia. 



It being thus shown that in Halesidota, "Walker (== Lophocampa, 

 Harris), two species which are quite distinct in the larva, are undis- 

 tinguishable in the d 9 imago, and that in Dryocampadse two species, 

 belonging to distinct genera, and the larvae of which are totally 



* There is one possible source of error as to the distinctness of Dryocampa bi- 

 color and Sphingicampa distigma which had escaped my attention. These two 

 supposed species were, it is true, bred in separate cages and kept separate when 

 buried for the winter, but in the spring the separate cages into whicli they were put 

 were filled with fresh earth taken from my door-yard. In this door-yard stand two 

 honey-locusts, from which I had obtained most of my larva3 of distigma in 1862. It 

 is barely possible, therefore, that some of the fresh earth placed in the cage in the 

 spring might have contained, unobserved by myself, a pupa of distigma ; but on the 

 supposition that my three specimens of hicoLor were bred from such pupse, it is 

 necessary that this improbable thing should have happened, not only once in the 

 spring of 1862, but twice in the spring' of 1863. I am the less inclined to believe that 

 this could have been the case, because Dr. Fitch has remarked that D. stigma (im- 

 ago) " can sometimes scarcely be distinguished " from D. senatoria imago, and so 

 far as regards the coloration I can confirm this fact from my own experience. Yet 

 the larvae of these two species are very different. (See Fitch, iV. Y.Sep., Vol. ii., 

 $.323.) Mr. Edwards writes me word that "bethinks in D. pellucida and D. 

 stigma there is a great resemblance between either the cT d or the 9 ? > he is not 

 certain which." 



