48 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
£gg.—The egg is longish oval, and measures just over a 
millimetre in length. It is white in colour. 
Larva.—The full-grown caterpillar measures three-quarters of 
an inch, or a little over, in length. It has a round black hairy 
head, with a single ocellus on each side. On the upper surface, 
all down the back, the colour is grey-green; the sides are lighter ; 
the under surface is yellowish-green. If one uses a lens there 
will be seen on the abdominal segments transverse rows of 
minute warts with spines. The spiracles along each side are 
brown. The legs number twenty, viz., three pairs of thoracic 
legs, which are black, and seven pairs of abdominal legs, which 
have the colour of the underside of the body. The head is 
followed by twelve segments or joints—1, 2 and 3 are thoracic 
joints, and each bears a pair of legs; 4 to 12 inclusive are abdomi- 
nal joints; 4 has no legs; 5, 6, 7, 8, 9 and ro have each a pair of 
legs ; 11 has no legs; and 12, the last joint, carries a pair of legs. 
Packard! describes the caterpillar as moulting three times, 
and so distinguishes four stages of larva. On hatching, the head 
is very large and dusky green, not black; neither are the 
thoracic legs black; the body is uniformly pale green. After 
the first moult the head and thoracic legs are black; the body 
is wrinkled, but no warts show. After the second moult the 
upper surface is grey-green, and the transverse rows of warts 
appear. The caterpillar attains its full size after the third 
moult. The moulted skins can be seen wound round or 
attached to the leaves. 
Excrement.—The castings (excrement) of the caterpillar are 
longish, cylindrical, and somewhat square cut at the ends. The 
castings observed on the ground will afford a hint as to the 
presence of the larve. So numerous were the caterpillars in 
some parts of the attacked area, that in July their excrement 
falling on leaves below suggested the patter of rain drops. 
Cocoon. The cocoon, strong and leathery or parchment-like, 
is dark brown in colour; it is cylindrical in shape, with rounded 
ends ; the inside is smooth, the outside shows a raised network 
pattern. The size may be taken on the average as between 
2 inch and } inch. I have some from the soil less than 3 inch, 
but these may contain parasitized larve. 
1 Fifth Report of the United States Entomological Commission: ‘‘ Forest 
Insects,” 1890. 
