302 Mr. R. Meldola on the Amount of Substance-waste 



the breeding of Papilio Ajax ; and these seemed to furnish data 

 fitted for testing my conclusions. 



Papilio Ajax is a polymorphic species inhabiting North 

 America, presenting the three following Avell-defined forms : — 



1. Papilio Ajax, var. Walshii, Edwards. 



2. , var. Telarnonides, Felder. 



3. , var. Marcellus, Boisduval. 



These three forms differ in many specific characters, and 

 were long recognized as distinct species. They form a series 

 graduating in size, Marcellus being the largest and Walshii 

 the smallest. The first to appear on the wing in the year is 

 Walshii ; this is followed by Telamonides, and this in its turn 

 by Marcellus. The larvai of Walshii are described by Mr. 

 Edwards as being very uniform in colour and marking ; those 

 of Telamonides are similar to Walshii " up to the second moult, 

 after which there is a wide divergence, some retaining a re- 

 semblance to Walshii,^^ others presenting several variations. 

 " The larvas of Marcellus combine the variations of Walshii 

 and Telamonides.'''' The specific identity of the three varieties 

 was proved by rearing them all from one batch of eggs. Mr. 

 Edwards thus sums up the results of his whole series of obser- 

 vations : — " IF«?6;/«// produces Walshii^ Telamonides^ andil/ar- 

 cellus the same season, and its own type in the spring ; Mar- 

 cellus produces successive broods of Marcellus the same season, 

 and occasionally Telamonides (individual taken in September 

 1870), and the last brood produces TFa/s/m and Telamonides iiv 

 the spring ; and whenever any of the chrysalids of either brood 

 of Marcellus pass the winter theyproduce the other two varieties, 

 and probably sometimes their own type (individual taken in 

 April 1867). The chrysalids of Walshii that pass the winter 

 of 1871-72 will produce Walshii ov Telamonides.^^ The most 

 important difference between the varieties, so far as our present 

 purpose is concerned, is that in the duration of the larval and 

 pupal periods. The duration of the different stages in the 

 three forms is shown below : — 



Egg. Larva. Cbrysalis. Total. 



Walshii 7-8 daya. 22-29 days. 14 days. 43-51 days. 



Telamonides.... 4-5 „ 15-18 „ 11-14 „ 30-36 „ 



Marcellus 4-5 „ 12-19 „ 11-14 „ 27-38 „ 



Here, therefore, is a species presenting varieties differing in 

 size and in the duration of their larval and pupal periods. It 

 is easy to calculate whether any relationship exists between 

 the size of the insect and the ratio of the pupal to the larval 

 period ; and on making the calculation I found that tliere was 

 a relationship, but exactly the reverse of that which would be 



