AGRIADES THETIS. 387 



viewed sideways, but looked at from above, the loss of blue is so short, 

 if it takes place at all, that it only appears to give a twinkling appear- 

 ance to the insect, and its forewings are seen then to be somewhat 

 pushed back as in the case of most other blues. A $ observed in the 

 Via Mala, August 21st, 1907, left the flowers and flew along the road, 

 when it seemed to advance much more warily and quickly, and the 

 blue upperside seemed to be quite continuously in sight. When thus 

 active, the $ can be very pugnacious, although it comparatively rarely 

 attacks another $ of its own species ; we have seen it repeatedly assault 

 Polyommatus icarus, and, at Folkestone, Hipparchia semele has more 

 than once been observed as the object of its enmity; whilst once, high 

 on the Wormser Joch (August 13th, 1908), a bevy of quarrelling 

 " blues" were netted, consisting of 3 $ A. coridon, 1 $ A. tlietis (bellar- 

 gus), and 3 $ Albulina pheretes. When it settles in the full sunlight, it 

 adjusts itself so that the sun falls directly on its wings, but it seems to 

 matter little whether its head or tail is upwards, so long as it obtains 

 the full effects of the sun's rays ; at this time, it rarely stays long in 

 one position, and almost continuously moves its hindwings wheel-like, 

 alternately up and down, this movement frequently occurring when 

 the wings are drawn up over the back, the hindwings being slightly 

 lowered during the movement, as well as when the wings are let dowm 

 somewhat, when the costa of the hindwings is apparently pressed very 

 closely to the underside of the inner margin of the forewing. When 

 the insect is sunning, the wings are let down until they are about 20° 

 or 30° from the horizontal, the forewings thrown well forward, and 

 the hindwings pulled well back and under the abdomen, so as to show 

 the dark costa of the hindwings, choosing a piece of hot bare chalk 

 or a prominent point on the herbage. When the butterfly w 7 alks, 

 the legs on either side move alternately, but when about to fly, the 

 forewings are drawn quickly backwards and downwards, and the move- 

 ment of the body occurs simultaneously. This species is attracted in 

 hot weather to the puddles on the pathways in the lower alpine valleys 

 and elsewhere, but in less abundance than some other species, e.g., 

 just below Bourg d'Aru, in August, 1896, we noted the £ s consorting 

 with swarms of Hirsutina dam on, Agriades coridon, etc., at the little 

 runnels crossing the roadways, whilst in August, 1908, we also saw it 

 at the rills in the ascent to the Ofen Pass, with Agriades coridon, 

 Aricia donzelii, etc. In June, 1899, herds of A. tJwtis with Cupid o 

 sebrus, C. minimus, Polyommatus escheri, P. icarus, and Cyaniris 

 semiargus w T ere observed on the little islets of rich black mud, 

 in the bed of the Eaux-Chaudes stream just above the baths 

 near Digne, sucking the moisture in the sun (Rowland-Brown), 

 whilst Prideaux notes (in litt.) that the habit, so frequently noticed 

 abroad, of the imagines coming down to drink at the roadside puddles, 

 w r as observable in hot summers on Reigate Hill, and Prout writes 

 that, on certain days about August 20th, 1896, near Ventnor, it was a 

 sight to see this insect fly up in clouds from the warm chalk, stones, 

 animal droppings, etc., on Boniface Down. But the butterfly is not 

 always active in the hot sun, for it loves also at this time to feed at 

 flowers, and is then barely to be disturbed ; in the spring, in Britain, 

 flowers of thyme and Lotus are among its chief attractions, in the 

 autumn, thyme, Centaurea scabiosa, and a yellow hieracium also offer 

 great attractions, and Prideaux notes that the $ s of this species, 

 together with those of A. coridon, Polyommatus icarus, and Aricia 



