the Life History of Polyommatus eros. 475 



April 1. — Has commenced to eat after some 6 days' fast. 



April 2. — No. 2 has not yet changed. No. 1 is eating 

 very deliberately, he eats the whole thickness of the leaflet 

 (which is however much slighter than the strong leaves 

 found on the plant in summer). 



At rest it is about 5*5 mm. long, 2'3 mm. broad at 1st abdominal, 

 narrowing just appreciably to 7th abdominal and then rapidly 

 to the rounded posterior extremity. The colour is a rather dark 

 apple green, faintly paler, but not approaching yellow along the 

 dorsal ridges. The hair bases are numerous and rather dark, but 

 too small to produce much colour effect except along the dorsal 

 and lateral ridges. The spiracles are conspicuous, brown, the 

 prothoracic plate is dark and so very visible. The lateral flanges 

 stand out as very definite " flanges," as they probably do not do 

 when the larva is full fed. 



The dorsal and lateral hairs look strong and stiff, dark, brown 

 rather than black, 6 or 8 on each eminence, longest about 0*5 mm. 

 long. The honey-gland is obvious but not conspicuous. The 

 fans are rather conspicuous white spots, they have been seen partially 

 everted and then are very conspicuous. 



No. 1.— Died April 3rd. 



No. 2. — On April 9th had not changed, remained lethar- 

 gic till yesterday it eat a little ; it has one or two ominous 

 black spots. 



It was dead a day or two later. 



My efforts to rear the larva from the egg having thus 

 failed, the only available resource was to find the larvae 

 at home in the spring, and so, finding I could manage to do 

 so, on the 23rd May 1914, I went to Le Lautaret. The 21st 

 and 22nd had been very fine, warm days, the 23rd looked 

 doubtful, but for three hours in the afternoon I found it 

 warm in the sun, although there was a strong wind, at 

 the locality (7000 odd ft.) where Oxytropis campestris was 

 most abundant. The first plant I looked at was one of 

 sainfoin, and on this I found a larva of A. thersites conspicu- 

 ous about the centre of the plant, leaves 2|- to 3 inches 

 long. The few further plants of Onobrychis I looked at did 

 not afford another. On Oxytropis I found four larvae all 

 rather small, so small that one could not be sure what 

 they were. The 24th it rained all day. On the morning 

 of the 25th, in a rather cold wind, I again looked for larvae 

 in the same locality, and found 8 or 10, again rather small, 

 on Oxytrojyis. 



