162 BRITISH BUTTERFLIES. 



used Plebeius exactly in oar modern sense, i.e., as a group name next 

 above species, and we feel that time will probably support our con- 

 tention that it must be so used. In 1804, Latreille gives (Nour. Diet. 

 Hist. Nat., xxiv., pp. 184-5, 199-200) a series of genera with their 

 respective types, of which one is : — 



Genus Polyommatus — JJesyeria argus — 

 which, however, has no effect on our work here, since Latreille used 

 argus (as did most of the French authors of this and earlier date) for 

 icarus. In 1806, however, Hiibner published his Tentamen, in which 

 he created Rustieus with type argus, Hb. nee Linn. If argus, Hb., be 

 considered congeneric with argus, Jjinn. = aego?i, Hb., Rustieus must fall 

 before Plebeius, [Linne,] Kluk. About 1818, Hiibner founded (Verz., 

 p. 69) the name Lycaeides also for argus (argyrognomon) , the type of his 

 genus Rustieus, of which it is, therefore, a synonym, and, like the latter, 

 falls before Plebeius. Under the name Lyeaeides, Scudder describes 

 [Revision, p. 33) the genus, as follows : — 



Head small ; front flat, very slightly tumid beneath, scarcely surpassing the 

 front of the eyes, fully as broad as they, scarcely half as high again as broad ; eyes 

 naked ; antennae scarcely longer than the abdomen, composed of about 32 joints, of 

 which the last 12 or 13 form the club ; palpi slender, nearly or quite twice as long 

 as the eye. Fore tibias a little more than five-eighths the length of the hind tibiae ; 

 middle tibiae scarcely four-fifths the length of the hind.pair ; first superior branch of 

 the subcostal nervure of the forewings arising in the middle of the outer two-thirds 

 of the upper border of the cell ; the second midway between it and the origin of the 

 first inferior subcostal nervule ; cell somewhat more than half as long as the wing. 



The Plebeiid egg (sens, restr.) is large in size, compared with that of 

 some of its allies, so far as can be judged from the few known and 

 described. Scudder notes it (Butts. New. Eng., ii., p. 961) as white,, 

 tiarate, flattened above and below, covered with a delicate tracery of raised 

 lines, having a kind of wheel-pattern ; that of P. scudderii is described 

 at length (op. cit., p. 966). Of the two very similar European species,, 

 both P. argus (aegon) and P. argyrognomon Irybernate in the egg- 

 stage (the fully-formed larva coiled up therein till spring). [We believe, 

 however, that P. lycidas hybernates as larva.] The eggs of those 

 species that hybernate as larvae appear to be laid on the leaves and 

 stalks of the plants that provide food, the egg of P. argus (aegon) is, 

 apparently, not laid on the leaves but on the stems of its more 

 herbaceous food-plants, perhaps not even on the food-plants at all. 



The larvae of Plebeius are usually green in colour, modified with 

 yellow, red, and brown longitudinal and oblique markings; and usually 

 responding very markedly to the tints of their foodplant for protective 

 purposes. They are all provided with small, rather pointed heads and 

 long extensile necks (prothorax), which, when young, are inserted into 

 the cellular tissue of the leaf, the soft parts being cleared for some 

 considerable distance from the point of entrance. Scudder describes the 

 larvae (op. cit., p. 962) of the .Nearctic species as green, with or without 

 a dorsal stripe, and with faint and oblique lateral lines, the head capable 

 of being extended to a great length. He further details the feeding 

 habits of P. scudderii (op. cit., p. 968) stating that the young larva intro- 

 duces its head and very flexible and extensible neck, into a small hole, 

 made in the lower cuticle of a. leaf of Lupinus perennis, devours all the 

 interior of the leaf as far as it can reach, many times the diameter of 

 the hole, so that the Leaf looks as if marked with a circular blister 

 having a central nucleus, the nearly colourless membrane of the leaf 



