554 WOOD LEOPARD MOTH. 
a convenient cell in the tree, lining it with a fabric of mixed wood-scrapings 
and silken threads. Before it emerges from this retreat, it pushes itself through 
its burrow like a sweep ascending achimney, protrudes about half of the boay, 
and then issues from the chrysaiis shell, which it leaves within the burrow. 
The Woop LEOPARD MOTH, is a very prettily marked insect, though 
without the least brilliancy of colour. The caterpillar of this insect feeds 
upon the interior of many trees, seeming to prefer the wood of the apple, 
pear, and other fruit-trees. It is a naked, fleshy-looking larva, of alight yeliow 
colour, and having a double row of black spots upon each segment. Like 
the Goit-moth, it prepares a cocoon-like cell when it is akout to take the 
pupal form, but the lining is of stronger materials, cemented fiimly together 
with a glutinous substance secreted by the,insect. Tle mcth is-seldom seen 
until July, and is tolerably plentiful in some places, appearing to Le decidedly 
local and rather intermittent in its visits. 
THE family of the Bombycide includes several insects of inestimable 
value to mankind, the various siik- 
producing moths being included in 
its ranks. The con mon silk-woim 
is too familiar to need any notice, 
but as it is not generally known 
that upwards of forty silk producing 
moths exist in different parts of the 
world, a short history will be given 
of some of thern, together with a 
figure and a brief description of one 
of the finest species. All these in- 
sects secrete the silk in two large 
intestine-like vessels in the interior, 
which contain a gelatinous kind of 
WSS substance, and become enormously 
LESS large just before the caterpillar is 
WOOD LEOPARD MOTH.—(Zeuzera esculi) about to charge intoa pupa. ‘Both 
the silk organs. unite in a common 
tube at the mouth, technically called the spinneret, and through this tube 
the semi-liquid is ejected. As soon as it comes into contact, with air it 
hardens into that soft, shining fibre with which we are so familiar. 
If a single fibie of silk be examined through a good microscope, it will be 
seen to consist of two smaller fibres laid parallel to each other, like the barrels 
of a double gun, this structure being due to the double secreting vessels. 
The goodness of silk chiefly consists in the manner in which these semi-fibres 
are placed together. 
The caterpillar employs the silk for the purpose of constructing a cocoon 
in which it can lie until it has assumed the perfect form ; and proceeds with 
wonderful regularity and despatch in its work, its head passing from side to 
side, always carrying with it a thread, and the cocoon being gradually formed 
into the oval shape which it finally assumes. The few outermost layers are 
always rough and of poor quality ; these are stripped off, and the end of the 
thread being found, it is fastened to a wheel, and spun off into. a hank of soft 
yellow fibre. The colouring matter is very variable, sometimes being hardly 
visible, and at others giving the silk a bright orange tint. It fades much on 
exposure to light. 
THE family of the Arctiidae, so called because some of the hair-covered 
Jarvee have a bear-like look, is represented in England by many examples, 
some being really handsome insects, and others remarkable for some pecu- 
liarity in themselves or the larvee. ; 
