POECILOCAMPA POPULI. 478 



Vakiation of larva. — The study of Buckler's figures of the larva 

 of this species (Larvae Brit. Moths, pi. xlviii., figs. 2, 2a, 2c, and pi. 

 xlix., fig. 1) will give a much better idea of the forms this larva may 

 take, than any descriptions. Besides the form already described, i.e., with 

 a dorsal series of dark grey blotches, bearing the form of inverted urns 

 on all the segments following the prothorax, and through which runs 

 the darker dorsal line, with two acute angular marks of bright ochreous- 

 orange extending transversely within them (Buckler s Larvae, hi., pi. 

 xlviii., fig. 2a), there are : (1) A distinctly bluish form with orange- 

 red, transversely oblique, dorsal stripes, directed backwards on the 

 anterior segments (loc. cit., fig. 2). (2) A dark grey form with a small 

 round white spot margined with black on either side of the median 

 line on the meso- and metathorax, a pair of small yellow, and a pair 

 of larger blackish, dorsal spots taking the place of the trapezoidals on 

 the abdominal segments. Other modifications occur in the colouring 

 of the larva, but there is no evidence to show that the various forms 

 are hereditary, nor do they appear to be confined to special districts. 



Pupation. — The cocoon is remarkably small for the size of the 

 larva, and is almost always formed so as to be adherent to the base of 

 oak-trunks just beneath the soil (Merrin) ; Greene says the cocoon is 

 found on various trees— ash, poplar, &c. — in August and September, 

 sometimes firmly glued to the inside of a piece of loose bark or to the 

 tree itself, at others spun-up tightly among decayed leaves, dead 

 grass, &c. Sheldon notes pupae found under bark of wych-elm at 

 Derby, and Miss Miller that the tough cocoon is spun-up under bark 

 at Chelmsford. Burrows says that he finds the tough black cocoons 

 among dead leaves in hedgerows or attached to the upper surface of 

 cavities in roots of ash and oak ; Wolfe at Skibbereen obtains them at 

 roots of elm, and Bostock under loose bits of bark at Tixall ; Eddrupp 

 writes that the cocoons are fairly common in rubbish at roots of elm at 

 Bremhill, whilst Robertson generally finds them under the loose bark 

 of various large trees at Sketty Park. Other notes are : at roots of 

 oak in Worcester Park (Kaye), at roots of ash at Leek (Hill), at ash 

 roots (Moss), often made up in the forks of the small stems of oak in 

 June (Cross), on bark of willow (Clutten), at roots of isolated hawthorn 

 tree at Emsworth (Christy), at the foot of ash trees (Eaynor), at roots 

 of oak under moss (Grover), under the bark of trees, under moss on 

 rocks, and among rubbish at roots of willow near Hartlepool (Gardner), 

 in crevices of bark, of poplar and oak near Selby (Ash), at roots of oak 

 at Worcester (Hancock). 



Cocoon. — The cocoon is composed outside of particles of extraneous 

 matter (earth, wood, leaves, moss, &c.) spun together with silk. It 

 averages about 17mm. in length, and 11mm. at its widest part. It is 

 of about the consistency of good notepaper, rather tough, covered inside 

 with coarse whitish silk, but with a smooth appearance to the naked 

 eye. The imago escapes by means of a round hole at one end of the 

 cocoon, the piece forced oft", reminding one somewhat of the lid of 

 the cocoon of LacJnuis lanestris, but, owing to the difference in the nature 

 of the cocoon, the lid is not broken off in a single piece. The pupa 

 occupies very completely the whole space within the cocoon, and is very 

 firmly attached in its cocoon by its cremaster. Poulton states (Trans. 

 Ent. Soc. London, 1892, p. 448) that "four cocoons were spun among 

 leaves and twigs of Quercus cerris, these were quite black on all exposed 



