LEPIDOPTERA. 317 
Polyommatus. Some of these are of a reversed heart shape, with a 
thin peduncle arising between the two basal lobes, the apex being ter- 
minated by numbers of minute filaments often thickened at the tip. 
M. Deschamps has also made an extensive series of observations upon 
the manner in which these scales are implanted into the membrane 
of the wing, and has shown that the firmer fixing of them in the 
Bombycidz is owing to the base of the peduncle being clavate, and 
inserted into a similar-shaped cup. (Annal. Sci. Nat. February 
1835. pl. 3, 4.) 
Mr. Bowerbank has also subjected the scales of several species of 
butterflies to a similar investigation, with a nearly similar result, 
considering that the scales consist of at least two distinct layers ; 
the uppermost formed of numerous longitudinal and cross striz, 
covered or connected by a thin membrane more or less coloured, 
and the under one composed of a somewhat thicker and stronger 
membrane, of uniform texture, and without stria. The greatest 
breadth of the dark brown scales from the wing of Papilio Paris is 
but =1~ of an inch; the quill by which it had been attached to the 
wing is s)'55; the distance of the strie from each other, 75157; 
and the diameter of the longitudinal strize themselves, 571 ~~ of an 
inch. These strize Mr. Bowerbank seems to regard as canals. The 
internal diameter of these minute tubes, supposing them to be such, 
may be estimated at about ;;4,; of an inch. (Entomol. Mag. No. 
23. p. 304.) See also Read, in Taylor’s London and Edinb. Phil. 
Mag. for October 1839. 
The variations in the colours and markings of the wings are almost 
as numerous as the species themselves: the sexes also often differ 
materially from each other ; still some general principles are evident 
in the distribution of these colours and markings. Thus the Pontiz 
and Pierides are almost uniformly white ; Colias and its allies yellow ; 
the Fritillaries rich brown, spotted with black and with silvery spots 
on the under side ; Hipparchia and its allies ornamented with eye- 
like marks; the Lyczenz copper-coloured; the Polyommati fine blue, 
with small eyes on the under side ; the Zygaenz with red under wings ; 
the Noctuidee with an ear-like mark in the middle of the fore wings ; 
the Geometride with waved carpet-like marks. . 
Another peculiarity consists in the apparatus by which the two wings 
on the same side are retained together in the same line during flight, 
composed of a loop, in which a strong bristle plays (fig. 102. 8.): the 
