IQQ BRITISH BUTTERFLIES 



Section II. — (Polyomm.itiis proper.) First brancli of the post or subcostal vein free, and extending to tlie 

 costa of the fore wings ; the other veins as in Thecla proper. 

 SUBSECTION I.' — Hind wings witliout a subniarginal row of fulvous spots on the under side. 



A. Wings broad, liind wings rounded ; femalesblue above, with broad dark margin to the fore wings. P. Argiolus. 



B. Wings more triangular, hind pair more ovate. P. Cymon, Arion, and Alcon. 



SUBSECTION II. — Hind wings with a subniarginal row of fulvous spots on the under side, comprising all the 

 other species, which may be divided into groups according to the colour of the upper side of the wings in the 

 opposite sexes. 



DESCRIPTION OF PLATE XXXI. 



Insects. — Fig. 1. Polyomniatiis Argiolus, male (tlic azure blue Butterfly). '2. The female. 3. Showing the under side. 



Fii;. 4. Polyommatus Alsus (the Bedford blue Butterfly), fem.ile. 5. The male. 6. Showing the under side. 7. The Caterpillar. 

 8. The Chrysalis. 

 '■ Fig. 9. Polyommatus Acis (the Mazarine blue Butterfly), male. 10. The female. II. Sliowing the under side. 



1'lants. — Fia. 12. Medicago dcntieulata (Reticulated Medicago). 13. Astr.agalus Alpiuus (the Alpine milk-vetch). 



Tlie English names of P. .\rgio]us and P. Alsus seem to require reformation ; the fonuer seems inapproriately styled the azure blue, which 

 term does not at all describe its peculiar tint, "whilst others of the genus, P. Adonis, for example, might truly be styled " azure blue." I should 

 propose calling it the " light blue." The name of P. Alsus, " the Bedford blue,'' is still less desciiptive, for neither of the sexes is blue at 

 all, though in some individuals the male has a sort of purple gloss in certain lichts. The *' Bedford brown " would be far more intellicrible. 

 Godart, from whose figure 1 have talien the Caterpillar and Clirysalis, describes the larva? of Alsus as feeding upon Astragalus cicer ; but as that 

 plant is not found in England, I have figured au elegant British species instead. The Medicago, upon which it is probable tliat the larvie of some 

 of the Polyommati may feed, I have been induced to give a figure of, from the siugulaiitj- of its seed-vessels. — II. N. H. 



SPECIES 1.— POLYOMMATUS (PITHECOPS) ALSUS. THE BEDFORD BUTTERFLY. 



Plate X!i.\i. fig. 4—8. 



.SvNONYJirs. — Hesperia Ahus, Fabricius. Nomiades ^/.v;(.s, HUbner (Verz. bck. Srbmctt.) 



Papilio Alsi/s, Gmelin; Lenin, Pap. pi. 39, f. 3, 4; Donovan, PapUio mininuts, Es|ier, Schaffcr, ViUers. 



Brit. Ins. 9. pi. 322, fig. 1. Papilio Pseudolus, Borkhausen. 



Polyommatus Alsus, Stephens, Curtis ; Duncan Biit. Butt. pi. 31, 



f. 3 ; Wood, lud. Ent. t. 2, f. G2. 



This is the smallest of our British Butterflies, the expanse of the fore wings generally varying from ;5. to 

 1 inch. On the upper side the wings are of an obscure brown colour, with a slight blue glo.ss towards the base, 

 especially in the males, of which sex I possess a specimen, in which at least half of the atoms of the disk of 

 the wings are silvery blue : the female, on the contrary, is more obscure. The fringe of the wings is white ; on 

 tlic under side all the wings are of a light ash colour, with a slender black lunule at the extremity of the discoidal 

 cell ; half-way between this lunule and the hind margin of the fore wings is a transverse row of black, ocellated spots, 

 with white irides, the two inner ones being more confluent ; the hind wings have throe or four similarly ocellated 

 spots, irregularly placed in the basal half of the wings, beyond tlie middle of which is a waved row of seven or 

 eight similar spots ; and on the margin of these wings is a black spot, at a short distance from the anal angle, 

 unnoticed either by Ilaworth or Stephens, and several obsolete brown spots. The number of the spots on the disk 

 of the wings is, however, liable to variation. 



This plain-coloured little butterfly, remarkable for the great delicacy of the markings on the under side of the 

 wings, appears at the end of May and beginning of July, and occurs in a number of localities in different parts 



