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IX. A Contribution to the Life History 0/ Agriades thersites, 

 Cantener. By T. A. Chapman, M.D., F.Z.S. 



[Read March 18th, 1914.] 



Plates XXVI-LIII. 



In presenting my account of this species to the Society two 

 years ago, I promised myself, all being well, shortly to 

 learn something about its early stages. 



In 1912, however, searching for the larvae on Sainfoin, 

 I was only rewarded by finding those of A. damon and 

 P. argyrognomon (Ent. Mo. Mag., 1914, p. 22), and as 

 regards the imago, though I found specimens, I did not 

 hit off the correct place and season for success. 



In 1913 I was more fortunate. I was unlucky in not 

 meeting with the spring brood, but in July and August I 

 obtained specimens and ova. On the 20th July I met 

 with one specimen only, a very fresh male at Bourg d'Oisans, 

 and so, concluding that it was only commencing to come 

 out, I went for a fortnight or so to Le Lautaret, at some 

 6900 ft. of elevation, and was a good deal surprised to find 

 thersites there. On the 24th July, at some 400 ft. below 

 the Hospice, at an actual elevation of about 6500 ft., I 

 found thersites on the wing amongst wild Sainfoin in full 

 bloom, some going over, flying with icarus, damon, escheri, 

 argyrognomon, eros, miniyna, corklon, and other butterflies. 

 The minima were nearly over, as judged by numbers and 

 condition ; the thersites nearly all worn and damaged, with 

 a few $ $ amongst them. By the 29th thersites at this 

 locality were clearly nearly over. At this date I made a 

 note of species flying with it, to illustrate that its companions 

 were really rather of a subalpine type, and not, as I had 

 supposed to be the rule with thersites, of a less Northern 

 type than is found in the south of England. It must not 

 be forgotten that Le Lautaret is in many respects a very 

 exceptional locality, close to very alpine areas, for the 

 most part subalpine in its plants and insects, but possessing 

 many species that one hardly expects to find at such an 

 elevation. The species noted as more or less common 

 and flying with A. thersites were Erebia stygne, tyndarus, 



TRANS. ENT. SOC. LOND. 1914. — PART II. (OCT.) 



