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XII. Observations completing an outline of the Life History 

 of Lvcaena arion, L. Bv T. A. Chapma^t, M.D., 

 F.Z.'S. 



[Read October Gth, 1915.] 



Plates XLVII-XLIX. 



On June 2nd, 1915, I laid before the Society an account of 

 a small but important discovery as to the habit and food 

 of the larva of Lycaena arion, L., as it was attaining its full 

 growth in the spring. This showed that at this stage it 

 lived in or near the nest of Myrmica scabrinodis, Nyl., and 

 fed on the larvae of that ant, and pointed to the larva not 

 clearing the primae viae in the usual lepidopterous manner. 



I was of course very desirous of learning something of 

 the autumn habits of the larva, from the point at which all 

 previous efforts to trace its proceedings had, in spite of 

 prolonged investigation by many observers, quite failed. 

 With the light thrown on the matter by my spring results, 

 this seemed more hopeful, since there was now for guidance 

 the fact that the larva associated with ants and preyed on 

 their larvae, and whatever number of species of ant it 

 might thus parasitise, it was at least certain that Myrmica 

 scabrinodis was one of them. 



By the kindness of our President and Mr. Frohawk, I 

 obtained some eggs of L. arion in July, and in August had 

 reared some larvae to the critical stage. I am also much 

 indebted to Mr. Donisthorpe for advice and assistance in 

 regard to ants, and especially for two observation nests of 

 Myrmica scabrinodis, one of the type and one of the var. 

 sabuleti. 



Among other observations I made some very imperfect 

 ones in regard to Donisthorpea flava , De Geer. I have not, 

 either now or in previous years, met with any real evidence 

 of any sort to show that the larva of L. arion can live in 

 the nest of D. flava. Nor, on the contrary, is it surprising, 

 especially since any accurate knowledge is so recent, in 

 view of the difficulty of proving a negative, that there is 

 no proof that it cannot live with D. flava. But it remains 

 as a weighty circumstance that all the exertions that have 



TRANS. ENT. SOC. LOND. 1915. — PARTS III. IV. (jUNE) 



