62 [August, 



far, because if the least exposed to air it rapidly shrivels up, or when 

 confined in a tin just as rapidly turns mouldy ; although the larva 

 will, when pressed by hunger, feed on flowers and tender leaves of the 

 common garden balsam, yet it will not thrive unless it has occasionally 

 some of its natural food plant, the seed vessels of which it eats out 

 apparently in preference, though it also will eat the leaves if they are 

 in good condition. 



The habit of the larva, like that of many other Geometers, is to be 

 perfectly quiescent on the stem of the plant all day, looking rather 

 shorter and stouter than when it wakes up at sunset, and feeds, and 

 continues to do so at intervals throughout the night, for then it 

 stretches itself to the full extent as a very active looper, lively enough. 



When half-an-inch long, the young larva is very slender, and often 

 rests on a stem with its head and next two segments bent backwards, 

 and anterior legs extended free ; its colour at this stage is a tender 

 yellowish-green, more or less tinged with faint brownish-pink, and with 

 W'hitish sub-dorsal lines : after moulting, and during further growth, 

 its semi-transparent skin indicates very well, day by day, on w'hat it has 

 nourished itself from one night to another, whether on the flowers or 

 on the leaves of the substituted food of balsam, for at one time the 

 body beyond the thoracic segments would be light bluish-green, at 

 another time pinkish-green or much suffused with deep pink, and 

 whenever it could return to its natural food would become of a more 

 subdued tint of uniform yellowish-greenish. 



When full fed and about to change, it contracts in length a little, 

 and appeal's stouter while it loses its lively colouring, grows tor2)id, 

 holds on to any object occasionally with the anterior legs only, and 

 elevates the hinder legs a little, quite free : this curious posture I 

 observed with the first two larvae of 1876, when the leaves of balsam 

 were removed, and only a mixture of peat earth and leafy mould re- 

 mained in their cage, and by the next morning (Sept. 24th) both had 

 buried themselves. But in the case of the two larvse I received on 

 the 12th October, 1877 (one much smaller than the other), I saw in 

 the evening of the 15th the largest had crejDt between two leaves of 

 the balsam, and a few reticulated silk threads could just be detected 

 around it, and by the 19th it had evidently made lap, as the leaves 

 then withering had become closely twisted together in somewhat 

 of a cylindrical form : at this time the smaller larva, which previously 

 had fed fairly well, appeared to be dead or dying, but on placing it in 

 the sun for a few minutes, it revived and seemed lively, but the next 



