xv INSECTA : LEPIDOPTERA 215 



Type, : The Cabbage White Butterfly (Pieris Brassicae). 



This is an excellent example to study in order to get a 

 knowledge of the structure and habits of a typical Butterfly, 

 for it is all too plentiful ; also it is easy to feed, and it goes 

 through its metamorphosis without any concealment. The 

 different stages of its life-history are illustrated in Plate II. 

 Th E There are two broods in the year. The eggs 



may be found in May, or again in July or August, 

 when they are much more plentiful than earlier in the year. 

 They are small, yellow, conical bodies, prettily ridged and 

 ribbed. They are often to be found on the lower side of 

 a cabbage leaf, or of a garden nasturtium leaf, in clusters 

 of from six to a hundred. These eggs hatch in seven to ten 

 days, and the little caterpillars usually make their first 

 meal off their discarded egg-shells. 



The hairy little caterpillars at first keep more 

 or less together, eating tiny holes in the blade of 

 the leaf. When the first moult is imminent, they collect side 

 by side and remain motionless for two days. Then they dis- 

 card their head coverings, push their body skins off back- 

 wards, and speedily begin to feed again, continuing to do 

 so with little rest until once more a moult takes place. 

 After the third moult, they separate and feed alone, moulting 

 once or twice more before they are full grown. The skins they 

 have thrown off may be often found in clusters on the leaves 

 they have frequented. When full grown, the caterpillar is 

 about 1 J inches long and J of an inch broad ; its colour is pale 

 yellowish-green with three 

 yellow longitudinal lines. 

 The body is dotted all over 

 with little raised tubercles 

 that are black on the back, 

 and brown On the sides FIG. 145. The Larva of Pieris brassicae. 

 and underneath the body. 



From each tubercle arises a short, rather stiff hair. The body 

 consists of a head and thirteen segments, the last of which, 

 however, is hidden by the one before it, and so cannot be 

 seen in a surface view (Fig. 145). The three thoracic 

 segments behind the head bear, as in all caterpillars, three 

 pairs of five-jointed legs, each ending in a little curved claw. 



