Wlarvels of the Universe 951 
summer, and quickly commences to lay 
eggs, starting a second brood, which, 
after making their cocoons, hibernate 
during the winter, emerging early in 
May. Many parasitic flies attack the 
caterpillars during their feeding-time, 
piercing through the gall-grub, into 
whose body they first inject a dose 
of formic acid, to paralyze it. The 
parasite then lays an egg in the hole 
on the under-side of the gall, and 
this hatches on the fourth day into a 
white grub, which attaches itself by 
its powerful jaws to the body of the 
paralyzed Saw-fly grub, and there it 
remains for a fortnight, slowly but 
surely devouring the body. When full 
fed, it just rests by the side of its 
late host and changes to a naked 
chrysalis ; and when mature, the fly 
emerges, bites its way through the 
gall, and is soon at its work among the 
second brood of Saw-flies. 
Many of our British Saw-flies are 
more or less gaily-coloured, some being 
of a deep violet or green colour ; 
others with red or bright yellow bands 
across their bodies and the wings beau- COCOONS OF THE WILLOW SAW-FLY. 
tifully iridescent. In size they vary Crawling down from the Willow to the wood-strewn ground beneath, 
the grub crawls behind a suitable loose piece of bark and spins a brown 
from two inches and a quarter tO silken cocoon. These cocoons are sometimes to be found in clusters as 
three-eighths of an inch in expanse of many as twenty together. From the left-hand one in the illustration the 
[by Fred knock, FLS. 
] Fly has already emerged. 
wings. 
A number are very injurious to both our root crops, such as turnips, on the leaves of which the 
caterpillars of the ‘‘ Black Jack’ Saw-fly sometimes feed in immense numbers, doing a great deal 
of damage. Then the gooseberry bushes are attacked by another species, which completely denudes 
the bushes of every leaf and small gooseberry. Another attacks the pear-tree, and much resembles 
a small black slug. 
Perhaps the worst Saw-fly pest is the one which, as soon as hatched from the egg, eats its way 
through the half-grown plums, right into the soft stone, and is not content until it has completely 
destroyed the kernel; and then it bites its way through, falls to the ground, where it spins its 
cocoons, and waits for the next spring crop. 
THE DELICIOUS MONSTER 
THE tribe of plants to which belongs our common Cuckoo-pint or Lords and Ladies, includes 
some remarkable tropical representatives. For that matter our own native species is remarkable, 
but it is one of the weaknesses of human nature to despise what is common, and to value 
what is not easily accessible. If the Cuckoo-pint could not be obtained nearer than the Andes 
or the Malay Archipelago it would be grown in our greenhouses as a curiosity ; but as it may 
