THE CHALK HILL BLUE. 169 



They frequently crawled among the plants for a distance of 

 about a couple of feet, occasionally curving the abdomen down- 

 wards among the small plant-stems and grasses, and here and 

 there depositing an egg. I therefore dug up portions of the 

 turf, potted it, and placed a couple of females on each lot ; they 

 deposited ova on the 14th and 15th, on the stems of various 

 plants ; a few were laid upon the brown dead trefoil leaves, as 

 well as on the living leaves ; but the site generally chosen is 

 the intermingled stems of both plants and grasses. Another 

 female, placed upon a similar pot of plants, deposited about 

 fifty ova on September 10th, nearly all being placed upon the 

 stems, and a few upon the under side of the leaves of rock-rose ; 

 in all cases the eggs are deposited singly." 



The caterpillars do not hatch out until the following spring. 

 According to Buckler and Hellins, the only difference between 

 the caterpillar of this butterfly and that of the next species, 

 Adorns, is that the latter " has its ground colour deeper green, 

 with the hairs or bristles black, while Corydon has the ground 

 colour of a lighter, brighter green (a green with more yellow in 

 its composition), and the hairs light brown." 



The butterfly is common and often abundant in July and 

 August, chiefly the latter month, on chalk downs in Oxfordshire, 

 Buckinghamshire, Berkshire, Kent, Surrey, and Sussex ; it is 

 also found in the Newmarket district of Cambridgeshire and on 

 one chalk hill in Norfolk, according to Barrett, who adds : " on 

 the oolite as well as the chalk in Wilts, Dorset, Gloucestershire, 

 and Somerset ; and on limestone at Grange and Silverdale in 

 North Lancashire, in Lincolnshire, Westmoreland, and Cumber- 

 land. It has also been taken in Essex, Hants, Cornwall, and 

 in one locality in Glamorganshire. /Vvvvyvx^ cr^ £ 



Mr. Sydney Webb has stated that a dwarf form occurs pretty 

 regularly in a valley about two miles east of Dover, but that it 

 only appears to be found at odd times in other parts of England. 



Abroad, the species is found in Central Europe, also in the 

 Pyrenees, Aragonia, and the Balkan Peninsula. 



