The Origin of the Markings of Caterpillars. 233 



markings, The occurrence of numerous stages of 

 development of these markings is thus excluded, 

 and the study of the ontogeny therefore promised 

 to furnish less information concerning the phyletic 

 development of the genus than in the case of the 

 preceding genera. This investigation has never- 

 theless also yielded interesting results, and the 

 facts here recorded will be found of value in like- 

 wise throwing light on the causes which have 

 produced the markings of caterpillars. 



I shall commence, as in former cases, with the 

 developmental history. I have easily been able to 

 obtain fertile eggs of all the species of Smerinthus 

 known to me. Impregnated females laid large 

 numbers of eggs in confinement, and also bred 

 females of the commoner species can readily be 

 made to copulate, when pinned, and exposed in a 

 suitable place in the open air. A male soon 

 appears under these circumstances, and copulation 

 is effected as readily as though the insect were not 

 fastened in the way indicated. 



SMERINTHUS TILLE, LiNN. 28 

 The light green eggs are nearly spherical, and 



28 [Mimas Tilicz of Butler's revision. The author states that 

 this genus is " easily distinguished from Laothoe by the form 

 of the wings, the outer margin of secondaries deeply excavated 

 below the apex, and the secondaries narrow and not denticu- 

 lated." Here again we have a clashing of the results arrived 

 at by a study of the ontogeny of the larvae, on the one hand, 

 and the founding of genera on the characters of the imagines 



