Two typical male Chalk Hill Blues.

 

A male ab. fowleri with white replacing the dark fore wing bands.

 

The females are typically brown on the top wing surface.

 

A very rare colour form of the female ab. khaki.

 

This ab.tithonus (formally named syngraphy) is the all blue form of the female and is very rare in Britain.

 

Females with some blue on their wings are uncommon but do occur in some colonies. This one is approaching ab. semi-syngraphy.

 

Typical underside spotting of female (left) and male Chalk Hill Blues.

 

A rare ab. radiata form of the male.

 

This ab.ceaca has all the spots missing and is not as rare as the streaked forms, but still uncommon in most colonies.

 

Male Chalk Hill Blues nectaring on Carline Thistle. Bedfordshire, July 2006.

 

Chalk Hill Blue eggs are button shaped and laid in late summer on or near on Horse-shoe Vetch, the caterpillars only food plant. The caterpillar remains within the egg until the following spring. By late June the caterpillar will be full grown.

 

A larva attended by ants, which "milk" the larva's "honey gland".

 

When full grown the caterpillar builds a fragile cocoon under ground debris, and the caterpillar  then changes to pupa.