1865.] 129 



length the whole surface of the larva's body has a dark brown spotted 

 appearance ; when this stage of its economy is reached, it is a sign that 

 the time has arrived for the larva to throw off its old skin ; on the skin 

 splitting at the head, the larva gradually eats its way forward, and as 

 it feeds with the under-side of its body facing the upper surface of its 

 food, the dark horny legs on its second, third, and fourth segments, as 

 they successively make their appearance out of the old skin, become 

 very conspicuous ; the larva's head is then very pale brown, and has a 

 dark brown spot on each side, tip of mouth dark brown, the anterior 

 part of the body dull green, the posterior portion still remaining in its 

 old skin is not traceable, owing to the dull spotted state of the latter ; 

 at length, afte? feeding for ten hours, it entirely escapes from its old 

 skin, and remains motionless for some time. When the larva quits its 

 old skin, and continues its mine straightforward, it is difficult to detect 

 the locality of the cast-off skin, owing to its being full of frass ; but 

 sometimes at the first moment of moulting the skin splits at the side 

 of the larva's head, through which opening it gradually emerges. 

 When this occurs, the old skin can readily be detected, as it then 

 points in an opposite direction to that in which the larva is feeding. 

 When the larva re-commences feeding the body becomes pale green, and 

 the only part of the dorsal vessel discernable is the anterior portion, 

 which is dark green ; when the larva is nearly full fed the dorsal vessel 

 is yellowish-green throughout its entire length ; and when quite ftdl 

 fed it is no longer perceptible ; the body is then pale green, excepting 

 the ninth segment, which is yellow, seemingly as though the 

 yellowish fluid, which had first previously traversed the dorsal vessel, 

 had finally settled in that segment. The larva then quits its mine, and 

 wanders about in search of a suitable spot on which to construct its 

 ingeniously suspended cocoon. Immediately after the larva has com- 

 pleted its cocoon, it lies quiet therein for two or three days, after which 

 it throws off its skin for the second time, and enters the pupal state, 

 the cast-off skin remaining collected in a little heap outside the cocoon. 

 The anterior and posterior segments of the pupa are white, and the 

 remaining segments pale green; eyes coloui'less, the yellow tint 

 observable on the ninth segment is still visible in the pupa. After 

 some tlu'ee or four days, the feet, and the tips of the antennse, turn 

 dark, the eyes become encircled with a pale green tint, which shortly 

 afterwards retires, and then a minute black speck is faintly discernable 

 in the centre of each eye ; the specks slowly enlarge until they cover the 

 whole expanse of each eye, turning them shining black. The posterior 

 portion of each wing-case becomes blackish, and each of the second and 

 third segments has a mark on its back ; these latter marks sometimes 

 assiune a semi-circular form. About the ninth day the imago emerges 

 from the pupa, and the empty pupa skin retains the dark marks at the lo- 

 calities where the imago's feet and tips of uutcnua) lay during its pupation. 



