112 
[Ofl 
"The clean white silken cocoon is semi-transparent, and of a textnrj|| 
^'1 strongly reminds one of the skin immediately beneath the shell of an eg^ 
J that the silk is less opaque : it is placed among the twigs towards the cent 
the branch, but not attached to them, although the webs of the lary^ an 
' the frass, and also of the numerous spiders which it contains, prevent the p 
' bility of shaking it out : in spite of this, however, it is always quite clean." 
On the 18th of April, 1869, Mr. de Grey kindly sent me several larv^ with t 
tood-that IS to say, a mixed mass of birch twigs, decomposed leaves and 
matter containing many old cocoons and pupa cases, some small tufts of 
wool, and an old gun wad. 
I separated this mass to look for the larv^, but found that they immed 
began again to construct loose silken galleries and thus re-united the vj 
materials of which it was composed. 
At this date the youngest larva was about half-an-inch long, of a dull 
browmsh oUve-green; others were larger and darker, the colour darkening, 
the growth, until the full grown larva was almost black. 
When full grown, the length is from 1^, to ix inch; the form modera 
slender, cylindrical, nearly uniform in bulk throughout, the hinder se^. 
tapermg a little at the sides; the region of the spiracles puffed and wrinkled; 
segmental divisions deeply cut. 
The colour of the back is a blackish, bronzy-green, becoming paler, of an d, 
or ochreous-green tint along the spiracles, and on the belly and legs, the head , 
the 2nd and 13th segments; the plate on the second segment is margined in fil 
with blackish olive : a fine blackish midulating line, apparently caused by a d< 
wnnkle, runs along below the spiracles, which are inconspicuous, beino- off, 
surrounding colom-, and merely outlined with blackish; the tubercular dots m 
httle raised, each bearing a fine hair; the whole surface is shining and bro. 
looking. 
The first mature larva spun its cocoon on the 23rd of April, 1869 ; the cooi 
at first was soft and very flexible, of a brilliant silvery whiteness, its yielding s 
face readily betraying the movements of the larva within, but after a day or t. 
enough silk had been spun to make it firm and unyielding; its length is abiJ 
l-mch, Its breadth f ; in shape it is rounded at either end, very convex on both i^ 
upper and under surfaces, these curves not being continued round the sides, 1 1 
meeting there in an acute ridge. 
The imago makes its exit at one end, but the edges of the orifice close togetl' 
agam, and the pupa skin remains in the cocoon, which shows no change whatJ 
m appearance. I 
The pupa IS brown in colour, nearly half-an-inch long, stoutest at the thorr 
dimmishing in the ordinary way to the anal point, which ended in a she 
e. The old larva skin, though much shrivelled, showed it had been separa^ 
he crown of the head and down the back, and was left in contact with \ 
e of the pupa. ] 
The moths appeared on the 6th and 11th of July.-W.M. Buckler, Emsworth 
tfai 
