The Origin of the Markings of Caterpillars. 2 5 1 



Immediately before pupation, all the caterpillars, 

 both green and brown, acquire a lilac coloration. 

 The fifth stage lasts seven days, and the whole 

 larval development twenty-three days, the period 

 from the deposition of the eggs to the appearance 

 of the moth being only thirty-one days. 



I have treated of the polymorphism of Stella- 

 tamm in detail, not only because it has hitherto 

 remained unknown, and an analysis of such cases 

 has been completely ignored, 40 but more particu- 

 larly because, it appears to me, that important 

 conclusions can be drawn therefrom. Moreover, 



among exotic species ; and, looking at the phenomenon as a 

 whole, it is seen to be one of gradation. For instance, our 

 common " Blues" (Plebeius Icarus, P. Thetis, &c.) have females 

 showing a complete gradation between the ordinary blue male and 

 the brown female coloration. In a large number of specimens of 

 Callosune Eupompe in my cabinet, collected in Arabia by the late 

 J. K. Lord, there is a completely graduated series of females, vary- 

 ing from individuals having the scarlet tips of the fore-wings as 

 strongly developed as in the males, to specimens without a trace 

 of such colouring : and the same is the case with other species of 

 this and allied genera. In such instances it is only necessary 

 for the intermediate female forms to become extinct, in order to 

 have true cases of dimorphism. It is significant that in 1877, 

 when Colias Edusa appeared in this country in such extra- 

 ordinary profusion, large numbers of intermediate forms were 

 captured, these forming an uninterrupted series connecting 

 the normal female and the var. Helice. R.M.] 



40 [Many of our best describers of caterpillars, such as the 

 late Edward Newman, Messrs. Hellins and Buckler, &c., have 

 described the various forms of nurrierous polymorphic species, 

 but not from the point of view of the comparative morphology 

 and ontogeny of the markings. R.M.] 



