230 BRITISH LEPIDOPTEKA. 



recommenced feeding, but at first very slowly, and appeared to be in 

 a very weak and languid state. As the food passed into the stomach, 

 the anterior portion of the dorsal vessel (which before the larva began 

 feeding was invisible) became tinged with green, and after a short 

 interval its posterior portion assumed a darker tinge. As soon as the 

 larva had refreshed itself with a little food, it rested for a time, 

 and during this interval threw off the old covering of its head. (On one 

 occasion, as soon as a larva began feeding, after moulting, I watched 

 it narrowly from the instant it swallowed the first mouthful of 

 food to the moment it ejected the first pellet of " frass," and found 

 that it occupied precisely half-an-hour, thereby implying that it 

 requires that amount of time, after deglutition, for the food to be 

 digested, the nutritious properties extracted, and the coarse indigestible 

 portion finally ejected as frass.) After this partial moult, the larva, 

 as if trying to make up for lost time, fed with remarkable rapidity, 

 its jaws being in constant motion, and as it ate its way forwards, the 

 anterior portion of its body became stouter. By this time the larva 

 had fed for a space of six hours, and had so far extended its mine as to 

 enable it to withdraw half of its body from its old skin; the frass 

 then gradually began to accumulate in the partially thrown-off skin, 

 the latter serving as a receptacle in which the " frass" was deposited, 

 and as the larva moved the extremity of its body about within the 

 walls of its old skin, the frass was distinctly observable as it fell pellet by 

 pellet. The frass did not flow in a continuous line to the extremity of 

 the body of the larva, but appeared in pellets at the base of the ante- 

 penultimate segment ; each pellet then slid gradually down till it 

 arrived near the centre of the penultimate segment, when it seemed 

 to be taken in charge by the branched portions of two darkish 

 coloured muscles, and conducted to the point where the remaining 

 portions of the muscles lay parallel with each other down the posterior 

 portion of the penultimate and the anterior portion of the anal 

 segments; these muscles then immediately expanded, and received 

 the pellet of " frass," and guided it to their extremities, and then 

 deposited it near the middle of the anal segment, out of which it 

 gradually slid, and became intermixed with the other pellets of frass 

 in the mine. At the expiration of twelve hours, the larva succeeded 

 in entirely escaping from its old integument ; the frass, instead of 

 forming a continuous line down the centre of the mine as it had done 

 before the larva moulted, then assumed a scattered appearance ; this 

 change in its arrangement arising from the larva jerking its posterior 

 segments about each time it deposited a pellet of frass" (Entom. Mo. 

 Mag., iii., p. 28). 



Cocoon. — The cocoons vary much in size, from 2 mm. to 4 mm. in 

 length, and from 1-5 mm. to 2-5 mm. in width. The cocoon is 

 roughly oval in outline, but varies much in actual shape, some having 

 the two opposite ends almost equal, others with one end much wider 

 than the other. The colour, too, is variable, dull-brownish with a 

 faint greenish tinge is the most common tint, but some cocoons are quite 

 green, whilst others incline to yellow-ochreous. The rim is some- 

 what thinned off, but does not form a flattened flange, the strongly 

 domed part of the cocoon rising gradually from the margin to the highest 

 point, which is almost central. The edge of the rim is crenate, and has 

 a considerable quantity of loose flossy silk around it. The raised part of 



