POLYOMMATUS. 93 



ing species, Stainton writes: "P. adonis well deserves its name, 

 and is the most splendid Blue we have. P. corydon, however, 

 has a peculiar beauty of its own ; it reminds one of the soft, 

 silvery appearance of moonlight, whilst P. adonis recalls the 

 intense blue of the sky on a hot summer day." Mr. Barrett 

 also remarks respecting P. corydon : " A very beautiful insect, 

 of a colour very difficult to depict or describe, and rarely to be 

 seen in nature. I have seen the same colour in the sky in the 

 late twilight of a stormy day, on the patches of pale blue visible 

 between heavy clouds ; but no flower, and hardly any other 

 insect, seems to possess it. No doubt the peculiarity arises 

 largely from the presence of the white hairs, already men- 

 tioned, on the upper-side of the fore-wings, which this 

 species possesses in greater abundance than any other, except 

 the very singular P. dolus, a South European species." 



P. dolus, Hiibner, above referred to, is a species found in 

 Southern France, which belongs to a different group to P. 

 corydon, and has central rows of spots on the under side of 

 the wings, but no sub-marginal spots, and a straight white 

 stripe running across the hind-wings beneath, from the base, 

 towards the middle of the hind-margin. 



II. THE CLIFDEN BLUE BUTTERFLY. POLYOMMATUS 

 THETIS. 



(Plate XLVL Figs. I, 3<?, 2?.) 

 Papilio thefts^ Von Rottemburg, Naturforscher, vi. p. 24, no. 1 1 



(1775). 



Papilio bellargiiS) Von Rottemburg, /. c. p. 25, no. 12 (1775) ; 



Esper, Schmett. i. (i) p. 333, pi. 32, fig. 3 (1778); i. (2) 



P 29, pi. 55, figs. 2, 6 (1780). 

 Polyommatus beltargus, Kirby, Eur. Butterflies and Moths, p, 



48, pi. 14, fig. 7 (1879). 



