Ixxx 
from the body of the host. The eggs also are victimized in a similar manner by a 
minute species of Ichneumon fly, one of which has fortunately been obtained; it is 
probably one of the Chalcidide : all the transformations take place within the egg, and 
when fully developed the perfect Ichneumon fly emerges therefrom. No parasitic 
insects have as yet been found to infest the male. It appears to me that the name 
Anisomorpha buprestoides is an incorrect appellation, as this Phasma is isomorphous. 
Perhaps the name of Phasma graveolens would be less open to objection, and it would 
at the same time express one of its striking peculiarities, viz. the offensive fluid 
secreted by the glands.’ —Cuartes B. Kine. 
Mr. Bates observed that the author of the note was probably in error in attributing 
the name of Anisomorpha buprestoides to the species in question, which seemed to be 
a true Phasma, 
Mr. F. Smith remarked upon the peculiarity of all the transformations of the 
Chalcidite parasite taking place within the egg of the Phasma; such a mode of 
development was novel, if trne, but he suspected some error of observation. 
Mr. M‘Lachlan suggested that the cocoon of the Chalcis had been mistaken for 
the egg of the Phasma. 
Mr. A. R. Wallace requested the assistance of Members in making observations to 
enable him to clear up a difficult point. Mr. Darwin had arrived at the conclusion 
that, as a rule in the animal kingdom, brilliant colouring was due to sexual selection: 
being struck, however, by the apparent exception to this rule presented by the bright 
hues of many larve, principally of Lepidoptera, which, being sexless, could not owe 
their gaudy attire to sexual selection, Mr. Darwin had inquired whether Mr. Wallace 
could suggest any explanation of this seeming contradiction of the rule. A theoretical 
explanation occurred to him, and it was for the purpose of ascertaining whether this 
theory was well or ill fuunded that he asked the aid of others. Many caterpillars were 
mimetic, imitating the leaves or flowers on which they fed, and thus obtaining protec- 
tion from their enemies; others were hairy or spinose, and were probably thereby 
preserved from attack ; whilst others again possessed neither of these modes of protec- 
tion, but were conspicuous by their lively coloration. Holding that nothing in nature 
was without its cause, nothing without its object, and believing in the principle of 
natural selection or the preservation of the fittest, he concluded that this conspicuous 
colouring must be in some way useful to those larve which were endowed with or had 
acquired it; but in what way was it useful to them? Just as certain moths were 
agreeable and others distasteful to birds, so also he did not doubt that certain larvae 
were agreeable and others distasteful to birds; but distastefulness alone would be 
insufficient to protect a larva unless there were some outward sign to indicate to its 
would-be destroyer that his contemplated prey would prove a disgusting morsel, and so 
deter him from attack. A very slight wound was sufficient to kill a growing caterpillar, 
and if seized by a bird, even though afterwards rejected as nauseous, its death would 
nevertheless ensue; the distasteful larve therefore required some distinctive mark, 
something by which they may be contrasted with and separated from the agreeable 
larve, in order that they might be freed from the attacks of birds. Brilliant coloration 
would be such a distinction as was required ; the larve which were attractive to birds, 
when not exterminated, were doubtless preserved from extinction by other protective 
qualities; whilst those larye which were distasteful to birds, and were not protected 
