THE SWALLOW-TAIL AND THE 'WHITES' 143 



of the same species as the two other very common * Whites.' The 

 three Large, Small, and Green-veined are so much alike in 

 general colour and markings, and so similar in their habits and in 

 the selection of their food plants, that the non-entomological, not 

 knowing that insects do not grow in their perfect state, may 

 perhaps regard the larger and the smaller as older and younger 

 members of the same species. But no they are three distinct 

 species, exhibiting to a careful observer many important marks by 

 which each may be known from the other two. 



On Plate I (fig. 3) will be seen a picture of the female Brassicce, 

 in which the following markings are depicted : On each fore wing 

 a blotch at the tip, a round spot near the centre, another round 

 one nearer the inner margin, and a tapering spot on the inner margin 

 with its point toward the base of the wing. On the hind wings 

 there is only one spot, situated near the middle of the costal 

 margin. 



The male may be readily distinguished by the absence of the 

 black markings on the fore wings, with the exception of those 

 at the tips. He is also a trifle smaller than his mate. 



This butterfly is double-brooded. The first brood appears in 

 April and May, the second in July and August ; and the former 

 the spring brood which emerges from the chrysalides that have 

 hybernated during the winter, have grey rather than black tips to 

 the front wings. 



The ova of Brassica may be found on the leaves of cabbages in 

 every kitchen garden, also on the nasturtium, during May and 

 July. They are pretty objects (see fig. 10), something like little 

 bottles or sculptured vases standing on end, and are arranged 

 either singly or in little groups. 



As soon as the young larvae are out from ten to fifteen days 

 after the eggs are deposited having devoured their shells, they 

 start feeding on the selfsame spot, and afterwards wander about, 

 dealing out destruction as they go, till little remains of their 

 food plant save the mere stumps and skeletons of the leaves. 



The ground colour of the caterpillar is bluish green. It has a 

 narrow yellow stripe down the middle of the back, and two similar 

 but wider stripes along the sides ; and the surface of the body is 

 rendered somewhat rough by a number of small black warty pro- 

 jections, from each of which arises a short hair. 



When fully grown, it creeps to some neighbouring wall or 

 fence, up which it climbs till it reaches a sheltering ledge. Here 



