1885.] Colouring of Phytophagous Larvce. 271 



1873, p. 155. He explains the relation between larval and vegetal colour- 

 ation, by supposing that the larvae have been rendered transparent by 

 natural selection, and that thus the vegetal colours are themselves 

 seen and give the colour to the larvae. He points out that internal 

 i'eeders are not green (their food being without chlorophyll), and he 

 quotes Chautard (" Compt. rend.," January 13, 1873) as stating that 

 he had discovered chlorophyll in the tissues of insects. 



Mr. Meldola further expands this theory in his editorial notes to his 

 translation of Weismann's " Studies in the Theory of Descent," 

 Part II, " On the Origin of the Markings of Caterpillars," &c. Here 

 he adduces the important evidence that "some few species of ISTep- 

 ticula (N. Oxijaccinthella, N. Viscerella, &c.) are green, although they 

 live in leaf -galleries where this colour can hardly be of use as a pro- 

 tection, but their food (hawthorn and elm) contains chlorophyll." He 

 also quotes Chautard ("Ann. Chim. Phys." [5], iii, 1 — 56) in addi- 

 tion to the previous reference to the same author, stating on this 

 authority that chlorophyll is a substance of great chemical stability, 

 and that it resists the animal digestive processes. On referring to 

 Chautard, I find that Mr. Meldola is mistaken in the statement that 

 Chautard had discovered chlorophyll in the tissues of insects. In 

 both papers referred to Chautard expressly states that the chlorophyll 

 came from the digestive tract of the insects (Cantharides) experimented 

 upon, and that he failed to obtain the bands after macerating the 

 elytra in alcohol. He indeed states that chlorophyll resists the 

 digestive processes, meaning that it is detected unchanged in the 

 faeces. In a note to one of the papers (" Ann. Chim. Phys.") Chautard 

 does not seem to be entirely satisfied with his proof of the absence of 

 chlorophyll in the elytra of cantharides. He states that if present 

 the chlorophyll must be much altered, and the colour of the elytra 

 cannot be due to it, and he points out that the colouring matter is 

 very insoluble in alcohol and ether. He alludes to Pocklington's 

 researches (recently quoted by Dr. MacMunn), but only mentions and 

 disputes the possibility of ascertaining the plant upon which the 

 cantharides fed by a spectroscopic examination of an extract of these 

 insects. 



Dr. MacMunn in a paper on Animal Chromatology in the " Pro- 

 ceedings of the Birmingham Philosophical Society" (1882 — 3, vol. iii, 

 Pt. II, p. 351), states that all previous attempts to find chlorophyll in 

 the colouring of insects have led to negative results. (There is one 

 partial exception to this in the case of Chautard's hesitation about 

 chlorophyll in the elytra of cantharides, and there is also Pocklington's 

 work on the same subject mentioned by Dr. MacMunn in a later 

 paper.) He states that by concentrating light on the integument of 

 the larva of Pieris Bapce and examining with a micro-spectroscope, he 

 found a band in the red which showed a resemblance to chlorophyll. 



