36 THE BUTTERFLIES OF NEW ENGLAND. 



mature larva they will readily be Ibuiul on the inner sides of the second and 

 third thoracic segments, appearing as oval pads, permeated by tracheal 

 vessels, situated just above and scarcely in advance of the base of the 

 tracheae in the respective segments, those of opposite sides directed toward 

 each other above. Their connection with the longitudinal tracheal canal, 

 from which arise the threads which penetrate them, is so intimate that they 

 Iiave been described as originating from them ; but in reality the wing- 

 arises at the very outset of larval life by the infolding of the hypoderm in 

 such a way as to resemble the half-inverted finger of a glove, the point of 

 which at the proper time pushes its way outward, and when the chitinous 

 outer coat is cast off appears as an external instead of an internal organ. 

 The legs and antennae, quite new structures, originate and develop in a 

 precisely similar way. In the larval condition all are infolded hypodermal 

 pockets. 



THE IMAGO OR BUTTERFLY. 



But O ! what teriii8 expressive may relate 



The change, the splendour of their new forniM state l' 



Their texture nor eoniposeil of tilmy skin, 



Of eumbrous flesh without, or bone witliiii, 



But something- than corporeal more retineil. 



And agile as their l)lithe informing mind. 



In every eye ten thousand brilliants blaze, 



And living pearls the vast horizon gaze; 



Gemnrd o'er their heads the mines of India gleam, 



And heaven's own wardrobe hasarray'd their frame; 



Each spangled l)ack briglit sprinkling specks adorn, 



Each plume iml)ibes tlie rosy tinctured morn; 



Spread on each wing the florid seasons glow, 



Shaded and verg'd with the celestial bow. 



Where colours blend an ever varying dye. 



And wanton in tlieir gay exchanges vie. 



Henry ^iixooviM.— Universal Beauty. 



External structure (PI. 62 : fig. 1). 



The head and appendages (87:25). The head of the imago, like that 

 of the caterpillar, is normally composed of a definite number of appendage- 

 bearing rings, but as these are greatly obscured by the excessive develop- 

 ment of some parts and the abortion of others, we will confine our description 

 simply to the parts as they appear, without reference to their morphological 

 relationships. 



The head as a whole is, in general terms, transversely obovatc, whether 

 viewed from above or in front, and is almost always much higher than 

 long and more or less flattened behind, next the prothorax. It is compact, 

 the sides occupied by globular masses of which the greater, and always the 

 whole of the front, portion forms the facetted eyes. It may be divided into 

 three principal areas : the front, the occiput and the flanks. The front 

 occupies the whole or most of the front of the head between the eyes with 

 the anterior half of the summit, is usually tumid to a greater or less extent, 

 and devoid of any great irregularities of surface. The occiput, which 



