THE SWALLOW-TAIL AND THE 'WHITES' 149 



fully grown, and ascends a stem of the food plant to prepare itself 

 for its long winter sleep. 



The chrysalis (Plate VIII, fig. 8) is a very peculiar object. Both 

 ends are much elongated and sharply pointed ; and the foremost 

 extremity stands out at an angle with the stem to which it is 

 attached. 



This butterfly should be looked for during April and May, but in 

 mild seasons it may often be met with in March. 



The Wood White (Leucophasia Sinapis) 



The distinguishing feature of this butterfly (see Plate II, fig. 1) 

 is the extreme lightness and delicacy of its build. Its wings are 

 narrow, and rounded at the tips ; and the only mark to relieve the 

 white ground of the upper side is a squarish blotch at the tip of the 

 fore wing, and even this is either very indistinct or entirely absent 

 in the female. The under surface is clouded with a pale greenish 

 tint. 



This insect may be looked for in May and again in August, in 

 paths and clearings in woods, where it moves along with a slow but 

 steady flight, hardly ever seeming to rest for a moment. It is not 

 by any means a common butterfly, but is very widely distributed, 

 and sometimes appears in considerable numbers in certain favoured 

 spots. Among the localities recorded may be mentioned Torquay, 

 Exeter, Plymouth, South Dorset, New Forest, Beading, Darent 

 Woods, Morecambe'Bay, Haslemere, Windermere, &c. 



The caterpillar is of a beautiful green colour, and is covered with 

 short whitish hairs. A darker green stripe runs down the middle 

 of the back, and a bright yellow stripe along each side. Its food 

 plants are the tufted vetch (Vicia Cracca), bird's-foot trefoil (Lotus 

 corniculatus and L. pilosus), bitter vetch (Lathyrus tuberosus), 

 and the everlasting pea (L. sylvestris). 



The chrysalis is a very beautiful object. Its colour is a delicate 

 green, tinged with pink ; and the wing-cases project in beautiful 

 curves much beyond the general surface. 



The Pale Clouded Yellow (Colias Hyale) 



The ground colour of this butterfly (Plate II, fig. 2) is very vari- 

 able. It is usually a sulphury yellow, and on this account the insect 

 is commonly known as the Clouded Brimstone ; but sometimes the 

 yellow is exceedingly pale almost white and tinged with green, 



