1864.] 419 



further appears that out of 3 sycamore-feeding tessrflaris compelled to 

 feed upon oak-leaves, one died in 6 days and another in 9 days, and the 

 remaining one disappeared ; and that four days after they had had their 

 food changed to oak, the tufts on their bodies approximated very re- 

 markably in color to those of Antiphola, though their pencils did not. 

 From these facts we may infer that tessellaris is not a mere Phytophagic 

 Variety of Antiplwla. 



It is an easy matter for the believers in the Creative Theory to cut 

 the knot, instead of untying it, by asserting that tesseUaris and Anti- 

 phola are simply distinct species in their sense of the term, and that 

 they have fed respectively upon the sycamore and upon oak, bass, elm, 

 &c. ever since their original creation. But in that case, assuming the 

 truth of the Creative Theory, how are we to account for the absolute 

 identity of their imagos. and for the further very remarkable fact that 

 these two forms are subject, as I have shown, p. 288, to six or eight 

 distinct variations, which occur equally in each of them ? If the colora- 

 tion of the two forms was plain and simple and without any definite 

 and elaborate pattern, as is the case for example in the dipterous genus 

 Cecidom^ia, there would be nothing so very wonderful in two distinct 

 species being undistinguishable in the imago, as we find to be some- 

 times the case in Cecidomyla. But the coloration, and more especially 

 the design or pattern of their wings, is so complicated and so diver- 

 sified, that I could as soon believe that the same pattern could be re- 

 produced twice over in a large and well-filled Kaleidoscope, or that, after 

 distributing the types of a book, they could be re-arranged so as to pro- 

 duce a fac-simile edition, undistinguishable from the first, or that the 

 same identical species had been created twice over in two separate 

 habitats or at two separate geological epochs, as that these two forms 

 were created originally as distinct species by the fiat of the Creative 

 Power. On comparing the two imagos, the impression is irresistible 

 to every unbiassed mind, that there must be a genetic connection be- 

 tween them, or in other words, that they are what I have called Phy- 

 tophagic Species ; which is further confirmed by the fact of the 3 syc- 

 amore-feeding tessrUat-is approximating in the coloration of their tufts 

 to A)itiphola, after feeding only for four days upon oak-leaves. They 

 certainly cannot be mere Phytophagic Varieties, for if they were, out 

 of the sixteen individuals that I endeavored to compel to change their 



