The Zoologist — April, 1867. 717 



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.'— Charles B. King. 



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 true, 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. Dnrwin 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 larva?, 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 founded 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 larva? 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 larva? 

 were agreeable and others distasteful to birds; but distastefulness alone would be 

 insufiicient 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 larva? therefore required some distinctive mark, 

 something by which they may be contrasted with and separated from the agreeable 

 larva?, in order that they might be freed from the attacks of birds. Brilliant coloration 

 would be such a distinction as was required ; the larva? which were attractive to birds, 

 when not exterminated, were doubtless preserved from extinction by other protective 

 qualities; whilst those larva? which were distasteful to birds, and were not protected 

 either by mimicry, hairiness, offensive smell, or otherwise, might be distinguished by 

 their colour from those upon which birds delighted to feed. Mr. Wallace's suggestion 

 therefore was that, as a rule, the brilliantly coloured larva? were those which were 

 distasteful to birds: it was on this point that he wished to collect observations and 

 statistics, and he should be glad if any who kept birds, and particularly indigenous 



