258 f^P"'- 



though there were exceptions of some colonies being uninhabited, and 

 others presenting several eggs. A large patch of Alliaria did not 

 afford a second e^g more frequently than a small one. These statements 

 might, no doubt, have to be modified according to the abundance of 

 the butterfly in different seasons, but it would remain true that each 

 butterfly lays her eggs solitarily and distributes them over a wide area. 



The Alliaria is undoubtedly the food-plant of cardamines in this 

 district ; I have found the eggs on turnips and charlock, but these 

 and the other Oruciferee it may affect are exceptional. 



The egg is very like that of P. rapcB, but is larger and darker ; 

 both are of the inverted vase shape, common in the Pieridce. In 

 cardamines the height of the egg is 110 mm., the greatest diameter, 

 •52 mm., the longitudinal ribs are thirteen in number, several coalescing 

 towards the top, so that the rosette at top has ten or eleven rays. The 

 colour, when first laid, is very pale pearly-green, almost white, getting 

 darker and passing through yellow to deep orange or almost brown. 

 Hapce (always laid on a leaf) is "90 mm. in height, "41 mm. in diameter, 

 has eleven ribs uniting into about seven at top. The colour is rather 

 greener, passing quickly into yellow and never darker than a pale 

 yellow. The bright orange colour makes the eggs of cardamines very 

 conspicuous amongst white flowers and green stems of the Alliaria, so 

 that they are easily found. 



It hatches on the eighth day, there is little doubt this period will 

 vary with the temperature. The larva takes from sixteen to twenty- 

 four days to feed up, the shorter period being that of a larva hatched 

 June 30th, and fed, therefore, during July. A still larger period is 

 probably the rule with larvae hatched early in May, as must often 

 happen. The following are the dates of moulting in two instances: — 



Hatched June 26th June SOth. 



Ist Moult „ SOth July 3rd. 



2nd „ July 2nd „ 5th. 



3rd „ „ 5th „ 8th. 



4th „ „ 7th „ 11th. 



Change to pupa „ 12th „ 19th. 



The newly-hatched larva attacks a small pod just below the 

 stigma, as it gets older it is less particular, but always feeds on the 

 pods and their contained seeds ; I never saw one touch a leaf. It has 

 the ordinary trapezoidal subdorsal and lateral tubei'cles. In subsequent 

 skins these gradually subside as the seven sub-segments become more 

 distinct with their rows of tubercular dot«, until, in the last skin, the 



