234 ALCON BLUE BUTTERFLY. 



This beautiful insect, which is extremely rare in 

 Britain, and not of frequent occurrence on the Con- 

 tinent, is said by Lewin to have been taken on Do- 

 ver Cliffs, Marlborough Downs, and on the hills near 

 Batb. Miss Jermyn mentions the commons at 

 Broomham in Bedfordshire, and certain places in 

 North Wales, as having afforded it. More recently 

 it was found by Mr Dale in the neighbourhood of 

 Bedford. 



ALCON BLUE BUTTERFLY. 



Polyommatus Alcon. 



PLATE XXXII. Fig. 2. 



Polyommatus Alcon, Lalreille — Hesperia Alcon, Fabr — 

 Pap. Alcon, Hubner. 



SuRFACEof the male violet-blue, with a rather wide 

 brown border to all the wings, and a dark crescent 

 on the disk of the upper pair ; of the female dusky 

 brown, tinged with blue towards the body. Under 

 side greyish in both sexes, with a central crescent- 

 shaped spot, bordered with white, on each wing; 

 behind this there is a curved row of rather large 

 rounded black spots, and two exterior rows of tri- 

 angular marks, all of them encircled with white ; the 

 basal half of the hinder wings is tinged with blue, and 

 bears a few scattered spots in addition to those cor- 



