THE STATE ENTOMOLOGIST. 167 



terous and Dipterous parasites beset them at every s-tep. The eggs, although so small and often so 

 heavily ridged, cannot escape the ovipositors of the tiny Pteromali, while in attempting to breed 

 caterpillars taken in the field, the chance is so greatly against the evolution of a butterfly, that 

 Hymenopterists actually choose this method of supplying their cabinets. 'Of two hundred larva 

 of Pieris brassicce,' Mr. Drewsen, of Denmark, writes to me, ' I obtained only twenty pupse, all the 

 rest were attacked by Microgcstcr glomeratus, and my own attempts with the larva? of Pyrameis Ala* 

 lanla, both in America and Europe, have been even more unavailing. These caterpillars seem to 

 be peripatetic banqueting halls of Microgasters and Tachinae. 



"Now it is a carious fact that while the globular egg of Limcnitis Misippus,* with its deeply-pitted 

 shell, defended by long filamentous spines, is constantly attacked by parasites ; and the gro- 

 tesque hump-backed, strangely-colored caterpillar of the same species is likewise infested to an 

 extraordinary degree, I have been unable to discover by very careful search any evidence that the 

 egg or larva of Danais Archippus is ever pierced by a parasite ; yet the egg is not small and only 

 lightly ribbed, and the caterpillar large, fleshy, smooth-skinned, and gaily banded, living on the 

 widely-separated leaves of Asclepias, with no attempt at concealment. The abundance of the ima- 

 go of the Danais is then due quite as much to the immunity of the egg and larva from the attacks 

 of parasites, as to any freedom it may itself enjoy from pursuit by insectivorous birds. [I.] 



" Although I have hunted butterflies for fifteen years, I confess I have never seen one in a bird' s 

 bill, and my faith in that method of lessening their numbers is very slight. Birds, too, must be 

 their greater foes in earlier life; and the chances of living, which are certainly against them 

 before they take wing, seem afterwards rather in their favour, at least, until they have accom- 

 plished their mission. [2.] 



"If, then, such an extraordinary element as Mimicry is to be summoned to the aid of Natural 

 Selection, and can perform its task in such a masterly manner, why has it been made to waste its 

 energies upon unimportant material? If the object of the resemblance be protection, why does not 

 the unfortunate caterpillar of the Limenitis mimic the more favoured larva of the Danais ? [3.] 



" I cannot now consult the writings of Messrs. Wallace and Bates, nor do I remember their 

 statements respecting the abundance of the mimetic species compared to that of its normal congen- 

 ers. In my own country Limcnitis Mis ppusis, as a general rule, more common than L. Ursula, but 

 the difference in their numbers is not very marked. It is by no means as great as one would expect 

 had Mimicry in the imago state so strong a protective power as has been assumed. [4.] Two close- 

 ly allied species occupying the same geographical area, do not often occur in the same abundance, 

 whatever be the cause, and the disparity in numbers in these two species of Limenitis is no greate 

 than occurs in many instances where mimicry plays no part. [5.] " 



[1.] No one will deny the facts, after what I have already set 

 forth. 



[2.] Such an experience from a butterfly hunter surprises me 

 Individually I have on several occasions seen butterflies captured by 

 birds, and have seen Dragon-flies dart after them. Any amount of 

 evidence might be collected on this head, and Mr. Scudder has already 

 been answered by Mr. Arthur G. Butlerf of the British Museum, 

 who mentions often having seen birds catch and devour the. 

 unprotected species upon the wing, while he has received- 

 abundant evidence respecting the immunity of the l^<i/tai& 

 group. " T. G. B." of St Johns College, Cambridge, has also 

 often seen the common English sparrow capture Vanessa urllcce 

 and Pieris rapce\; while Mr. Wallace has shown that great numbers 

 of butterflies are destroyed on the wing by insectivorous birds such 

 as jacamars, trogons and puff-birds, and gives conclusive evidence 

 that while our Disippus congeners, the Yi/mphalidte, suffer such per- 

 secution, the Archippus congeners do not. § Thus, though there 



*The reader must bear in mind that Misjpptis is but a, synonym for Disippus. 



| Nature III, p. 165. 



% Ibid, p. lGfi. 



§ Contributions, etc., p.. 79-. 



