the Life History of Polyommaius eras. ill 



At Le Lautaret in 1913 the butterflies in captivity laid 

 freely on Oxyfropis campestris and Astragalus aristatus, 

 and the larvae eat both these plants with equal readiness. 

 Phaca astragalina ( ? ) was less welcome to butterflies for 

 laying, and to larvae for eating, but was obviously quite a 

 practicable food-plant. 



The egg is almost exactly 0*5 mm. in diameter and about 0"26 mm. 

 high. The top can hardly be called flat, certainly not as it is in 

 coridon, etc., i. e. there is not a definite line at which the flat top 

 ends and the rounded side begins ; the curve of the side seems to 

 be continuous right on to the top, and falls a little into the micropylar 

 hollow. The micropylar area is about 0"075 mm. in diameter. Its 

 structure and the sculpture of the egg may be gathered better from 

 figures 14 to 17 than by long description. The cells of the egg 

 sculpture maintain their full size close up to the micropyle, where 

 there is a slight tendency for them to have their dividing walls 

 arranged radially. The cells are about 0*025 mm. in diameter, there 

 are distinct but very small knobs at the junctions of the walls of the 

 cells. 



The eggs are laid on the undersides of the leaflets of the 

 food-plant. 



When it leaves the egg, the larva eats approximately 

 the upper half of the shell, the instances are comparatively 

 rare in which it does not eat the whole of the top and more 

 or less of the sides, with some regularity all round. 



The newly hatched larva is less than 1 mm. in length, 

 nearly colourless, faint ochreous, hair bases dark, head 

 black, legs dark. In the 2nd instar it is rather larger, 

 much the same in colour, but the black hair bases are 

 very pronounced though less conspicuous after the larva 

 has grown a little, when it exhibits (difl;ering a little in 

 individuals) some traces of darker oblique markings. 

 The 3rd instar was assumed about 3rd September (some 

 earlier, some later). 



The larva in this instar is at first somewhat featureless. When 

 somewhat grown it may be noted as on Sept. 10, length 3'5 mm., 

 colour pale ochreous, with sufficient green to give an olive tone 

 especially to the front segments. Head black, legs ochreous like 

 body; outline (anterior or posterior view) angular, with the 

 Lycaenid dorsal and lateral flanges, the former rather rounded, but 

 both accentuated by the more abundant and longer hairs, which 



