Dr. T. A. Chapman on a Eurtypean Lycaena. 663 



thersites. It so happens that I have obtained thersiies 

 from various continental localities, but have not received 

 from any continental dealer a genuine European icarinus, 

 although I have several Asiatic specimens. 



Having obtained possession of Tutt's series of " teams," 

 or most of them, I found I had amongst them a sufficiency 

 of the new species (thersites) to enable me to reach some 

 very definite conclusions and to find several structural 

 details differentiating it from icarus. 



Tutt's habit of taking long series of each species from 

 each locality he visited, and especially devoting time to 

 this, wherever much variation occurred, has resulted in 

 this accumulation of material and it would have gratified 

 him to have found it so useful in this instance. 



Tutt, in his account of icarus ab. icarinus, no doubt 

 refers to our species, when he says (Brit. Butts., iv, 

 p. 159) in some places "as common as the typical form, 

 whilst in others again it is much more common and 

 almost racial " ; " in the lower valleys of the Dauphiny 

 Alps — Bourg d'Oisans, Bourg d'Aru, La Grave, Clelles, 

 etc., the form is abundant and almost racial in both sexes." 

 " It is very abundant in some seasons at Gresy-sur-Aix 

 (July 21, 1897, August 21, 1906) ; at Bourg St. Maurice 

 (August 1-7, 1898, August 1-5, 1905)." "Commonly 

 between Vex and Useigne on August 13, 1903." Other 

 references may be to thersites or to genuine icarus ab. 

 icarinns. 



That Tutt did not appreciate the full meaning of these 

 facts, was no doubt largely due to the circumstance that 

 in most cases there is absolute mimicry between thersites 

 and the form of icarus with which it occurs. 



This peculiarity of the species no doubt goes a very 

 long way to account for the refusal of Entomologists to 

 recognise it as distinct. When it occurs with icarus, it, 

 in each instance, imitates very closely the particular form 

 of icarus that occurs in that locality. This is very marked 

 in some specimens I have from the Tutt collection, of 

 which I may mention a large form from Pre St. Didier, 

 in which both species attain to 38 and 39 mm., a rather 

 less large one from Trelex of 36 to 87 mm. in both 

 species; the whole tone of colouring, intensity of orange 

 marginal spots, and other markings, make each such 

 association identical throughout in both species, except 

 of course as regards one or two distinctive points. There 



