LEPIDOPTERA. 83 



the butterflies. One of the most remarkable features in the wings of the 

 Heterocera, as distinguishtd from those of the Rhopalocera, is the existence of the 

 frenulum and retinaculum, briefly referred to above as the hook-and-eye arrange- 

 ment, with which the fore-wing is locked to the hind- wing. As already said, the 

 scales are modified hairs, which take a more and more perfect scale-like form 

 towards the centre of the wing. They lie in regularly arranged rows, over- 

 lapping each other, attached by a short stalk to a small forea or pit in the 

 membrane, to the number of many hundreds of thousands on each insect. Of 

 different shapes and sizes they are themselves, owing to their exquisitely sculptured 

 surface, objects of extreme beauty. And it is to these alone that butterflies and 

 moths owe their manifold tints, from the sombrest browns to the most resplendent 

 metallic greens, golds, and purples. 



The third division of the body is composed of a series of nine 



rings or segments, sometimes, as in the case of many of the moths, 

 tufted along the dorsal line, and also at the extremity. The spiracles, through 

 which the air passes to the tracheal system, lie along the sides of the abdomen, 

 while the organs of reproduction are placed at the extremity in both sexes. 



Butterflies and moths very rarely occur in the fossil state, owing 



no doubt to the delicacy of their integuments. Species of both, how- 

 ever, have been found in Tertiary deposits and some few in nodules of amber. The 

 Tertiary beds of the Florissant lake - basin of Colorado have furnished seven 

 species of butterflies, a dozen of moths, and one caterpillar. Two specimens of 

 hawk-moths are known, in one of which is well preserved the spirally-coiled proboscis. 

 Galleries of the leaf -mining Tineina have been preserved in leaves from the Chalk, 

 while other Lepidoptera, a few pearl-moths, owl-moths, goat-moths, silk-spinners, 

 burnets, and clear- wings, together with a few species of Vanessa and blues, have 

 also been recognised. 



The Butterflies, — Suborder Rhopalocera. 



As distinguished from the moths, the butterflies may be recognised as a general 

 rule by their antennae, which, as suggested by the name Rhopalocera, are slender 

 and abruptly clubbed at the extremity. In some cases, however, in the family of 

 the skippers, these organs are gradually enlarged towards the tip, which is itself 

 often slightly hooked. Butterflies have not, in any case the hook-and-eye arrange- 

 ment — the retinaculum and frenulum — by which the upper- and under- wings are 

 in the moths interlocked along their inner margins. The fore-legs are not always 

 well developed, and this is particularly noticeable in members of the male sex, 

 forming a reliable character in the broad subdivision of the Rhopalocera into 

 families. Butterflies are mostly diurnal in their habits, flying in the sunshine by 

 day, although a few take wing only towards evening. Their eggs and larvae differ 

 considerably in many respects from those of the moths, while the chrysalis is seldom 

 enclosed in even the finest network of silk, and in no case is wrapped in a distinct 

 cocoon, nor even buried beneath the earth, very rarely even close to the surface. 

 Usually the chrysalis is angular and blotched and speckled, with gold and silver 

 ornamentation; sometimes it is suspended to a branch or twig by the tail, and 



