PLATE XXYV. 
No.1.—The Azure Blue Butterfly (Polyommatus No. 6.—The Small Blue Butterfly, showing the 
Argiolus), Under side. 
No, 2.—The Female of the Azure Blue Butterfly. No. 7.—The Caterpillar of the Small Blue Butterfly. 
No. 8.—The Chrysalis of the Small Blue Butterfly. 
No. 3.—The Azure Blue Butterfly, showing the 
No. 9.—The Mazarine Blue Butterfly (Polyommatus 
Under side. 
Acis). 
iter oo Ue Buttery: (Polyommatis No. 10.—The Female of the Mazarine Blue Butterfly. 
= ued No. 11.—The Mazarine Blue Butterfly, showing the 
No. 5.—The Female of the Small Blue Butterfly. Tndeniaide: 
THE genus Polyommatus. This genus is principally distinguished from Chrysophanus by the 
bright blue colour of the upper surface of the wings of the males. The females are generally 
brown, or at all events of a duller colour than the males, and in a few species both sexes have 
the upper surface of the wings brown. The under sides of the wings closely resemble those of 
the insects assigned to the genus Chrysophanus, presenting, however, certain differences to be 
described in speaking of the respective species. 
The Caterpillars are onisciform, the head and feet very small, and scarcely observable with- 
out minute examination ; they are generally yellowish-green, variegated by markings of red, 
brown, or yellow. They feed generally on the foliage of Papilionaceous, and other low growing 
plants; that of P. Argiolus, however, feeds wpon the Holly, preferring the flowers. The 
Chrysalis is generally naked and attached to a branch of the plant on which the Caterpillar has 
fed ; but in some cases the Caterpillars burrow in the earth to undergo their transformation. 
This genus has representatives not only in all parts of Europe, but in North and South Africa, 
the East Indies, and North America, while but very few of the species are known in South 
America. 
Polyommatus Argiolus (the Azure Blue, No. 1). This is a very delicate and beautiful little 
Butterfly. The azure of the upper surface is of a soft and pleasing tone of light blue, and the 
under side a most delicate pale pearly gray, with the usual ocelli more slightly, but yet distinctly 
marked. The female differs in size, not as in the genus Chrysophanus from being larger than 
the male, but on the contrary smaller. In addition to the smaller size, the female may be at 
once distinguished by the more dusky colour, and by the deep black border of the anterior 
wings, and the dotted border of the hinder pair. 
The Caterpillar is described by Ochsenheimer as being of yellowish-green, with a double 
line along the back. It feeds on the flowers of Holly, and also it is said on those of the Ivy. 
The later brood probably do, as the Holly is out of bloom when they appear; some entomolo- 
gists, however, assert that there is only one brood of this pretty species, though specimens of 
the perfect insect are taken as early as April, and as late as August. 
The Chrysalis is brown, with a deep dorsal line. 
The Butterfly is very distinct in its habits, most of its congeners being generally found in 
gardens and plantations where Holly abounds. It is rather local ; but very widely dispersed, and 
in some places plentiful, being found quite in the North of England, but not in Scotland. 
