142 TRANSFORMATIONS OF INSECTS. 
growth; but some, especially those which live on fir trees, spin 
a cocoon. The moths have simple antennz, a rudimentary trunk, 
obtuse palpi, and tolerably large wings. The largest moths of 
this group belong to the genus //a/zas, and their trunks are not 
so rudimentary as is usual; moreover, they may be distinguished 
by the bright green colour of their wings. 
The Halas of the oak, Halias quercana, is the largest of 
the genus. The caterpillar is of a grey-green colour, and rolls 
up the leaves of the oak, and undergoes its metamorphosis in 
a cocoon, which it spins in the shape of a little boat turned 
upside down. The moth has two white bands upon its pretty 
bright green wings. Another kind, which is much smaller, is 
called the Green Tortrix. It does frightful mischief to oak trees, 
stripping them almost entirely of their leaves during the month 
of June. It rolls up the leaves in the shape of regular tubes, 
and undergoes its metamorphosis inside. 
The moths are drawn in the engraving one flying and the 
other at rest. The caterpillars are shown in different conditions, 
and the rolled-up leaf contains the pupa. 
Most of our vegetables are attacked by some caterpillars of 
this group, and the rose trees often suffer very much from 
them. One kind is very rare in England, but, unfortunately, 
is often so common in France that it produces great distress 
amongst those people that depend upon the cultivation of 
vineyards for their incomes. It is called Cenectra pilleriana. 
In England Mr. Stainton finds the larva in the seeds of the 
stinking iris, near Ventnor, but it is rare; in France, however, 
it attacks vine leaves, and does infinite mischief. The moth, 
which is not very large, has yellowish wings, which are darker 
behind. Its palpi are three times as long as the head, and 
this is a remarkable peculiarity. The moths fly in the month 
of July, and soon lay their eggs on the top of the vine leaves, 
in little flat packets, which are very readily seen. During the 
month of August the little caterpillars are hatched, but they 
do not begin to eat, although the temperature is high, and 
there is abundance of food; on the contrary, each one hangs 
itself by a silken thread, waiting to be moved to and fro by 
the breeze, until it touches the wooden prop of the vine, or the 
