unrecognised European Lycaena. 671 



The other difference in markings already alluded to is 

 in the double spot of the post-discal row at the tornus of 

 the forewing. In thersites these two spots are in line with 

 the one above them ; in icarus the lower one is moved 

 outward and often has the form of an oblique line. In 

 this, as in the disposition of the orange spots, thersites is 

 much more constant than icarus. Thersites does not vary 

 to the icarus disposition, though icarus may be found with 

 the arrangement that obtains in thersites. 



These distinctions in markings may well be useful in 

 the field, but of course have no such weight in deciding 

 the specific question as the structural differences. 



There is another definite distinction between thersites 

 and icarus, viz. in the androconia. One may imagine this 

 to be connected with a difference of scent, a desirable 

 quality in view of the resemblance of the species otherwise. 



These androconia present a considerable difference. One 

 might select one androconial scale of each species such 

 that it would be difficult to say which was which. But 

 with as few as half a dozen of each the discrimination 

 would be easy. 



The typical number of rows of dots is five in icarus and 

 four in thersites. Icarus may have four or six, thersites may 

 have three or five. Icarus usually has a row down the 

 middle of the scale in line with the shaft, in thersites the 

 two central rows are usually one on either side of this line. 



The distinction between the ribs of the androconial 

 scales might be described as thersites having four ribs, and 

 when it has five one is a trace of a rib along the margin. 

 Icarus almost always has some trace of a marginal rib, and 

 when it has only four strong ribs it has always a marginal 

 one on each side making six. This is a very common 

 form in icarus, whilst it is rare for thersites to have quite 

 marginal ribs. In size and form the two scales are much 

 alike, but that of thersites is shorter. The amount and 

 constancy of these differences will be better appreciated 

 by a reference to pi. LXXXIII. The ordinary scales 

 also differ in the two species. The two photographs, 

 pi. LXXXII, show the scales and androconia m sit2c, in 

 corresponding portions of the wings of both species. The 

 actual position is immediately in front of the basal portion 

 of vein 6 of the forewing. 



The scales in icarus are broader, flatter across their 

 ends; in thersites their hind margin is full and rounded, 



