51 



English species Arion; About 50 species inhabit Europe, of which ten have 

 been taken in Britain. 



The characters of the genus may be thus described : Antennae slender, club 

 thick, not gradually formed like that of Thecla; palpi rather long; eyes 

 sometimes hairy, sometimes naked ; wings very seldom with tails, those of the 

 male generally blue ; those of female generally brown. 



The caterpillars of all our British species, with the exception of Argiolus, 

 feed on papilionaceous, and various other low plants. 



Dr. Horsfield in the " Lepidoptera Javanica," divided the genus Polyom- 

 matus into two sub-genera, the first named P&taxgM, from the peculiar 

 aspect of the chrysalis. This sub-genus is represented in the British Fauna 

 by T. alsus. The sub-genus Polyommatus, is characterised by Dr. Horsfield 

 as having the margins of the hind-wings with the anal extremity angular, 

 and produced to a short, rounded point. Mr. Stephens, in his catalogue, 

 adopts these two sub-genera as sections, giving Argiolus and Acis, as well as 

 Alsus, as belonging to Pithecops. Dr. Horsfield, however, gives Alsus ex- 

 pressly as the European type of Pithecops, which he characterises by the 

 comparative narrowness of the wings, and it also possesses a peculiarity in the 

 arrangement of the veins of the fore- wings. Argiolus , on the contrary, has 

 broader wings than any other European species, and of a stronger texture. 

 Ochsenheimer divided the genus artificially into two sections, according to the 

 presence or want of a row of fulvous spots within the hind-margin of the 

 hind-wings. 



A few species have pale transverse lines on the underside ; these and one 

 or two others, have short and slender tails to the hind-wings. These 

 Hiibner placed in his genus Lampides. 



SUB-GENUS LAMPIDES. 



Hubner. 



Hind-wings with short and slender tails. 



Most of the species of this sub-genus are found in Asia and the Asiatic 

 Islands, and only four in Europe. 



POLYOMMATUS BCETICUS. 

 Long-tailed Blue* 



B(Eiicus, Linn. Boe'ticus, from Bcetica, as the Southern portion of Spain 

 was called in the days of the Roman Empire. 



