SHEATH -WINGED INSECTS 
287 
the “ miicro,” which lies in a sheath. When the beetle falls over, it arches its body into the 
form of a bow, resting only upon the head and the extreme tip of the abdomen, removes the 
spine from its sheath, and then drives it sharply back again. The result is that the central 
part of the body strikes the ground with such force that the insect springs into the air to a 
height of 2 or 3 inches. Then, turning half over as it falls, it alights on its feet. 
The Fire-fly of the tropics belongs to the same group. The luminosity of this insect 
proceeds from two different parts of the body, a brilliant yellowish-green light shining out 
through two transparent window-like spots on the thorax, while an orange glow is visible on 
the lower surface of the abdomen. The exact cause of the light is unknown, as is also the 
manner of its control by the 
insect. 
The same may be said 
of the common Glow-worm, 
in which the light proceeds 
from the lower surface of 
the hind part of the body. 
The male of this insect is 
winged ; the female is grub- 
like in appearance and wing- 
less. The grub itself, which 
may be found in autumn, is 
also luminous, and feeds upon 
snails. 
Another group includes 
a very large number of beetles 
of very varying character and 
appearance. Among these are 
the Oil-beetles, so called 
from their habit of exuding 
small drops of an oily liquid 
from the joints of their limbs 
when handled. The eggs are 
laid in batches of several 
thousand in holes in the 
ground, and the little long- 
legged grubs, on emerging, 
clamber up the stemsofflowers, 
and hide themselves among 
Photo by B. II. Bcnt.ey'j 
ISheJield 
COCKCHAFER ON DAISY 
^ -very destructive insect ivhich feeds on the leaves of trees. The larva devours the roots 0^ 
plants,! and is often so flentful as to cause very serious mischief 
the petals to await the coming 
of a bee. When one of the 
latter appears, two or three of 
the grubs cling to its hairy 
body, and are carried back to the nest, in which they live as parasites. One of these beetles 
may be seen commonly upon grassy banks in early spring. 
Allied to these insects is the Blister-beetle, or Spanish Fly, so well known from its use 
in medicine. It is a very handsome species, of a bright golden-green colour, occasionally 
found in Great Britain on the foliage of ash-trees. In many parts of Southern Europe it is 
extremely abundant. 
The beetles belonging to the large and important group of WEEVILS are characterised, as 
a rule, by the fact that the head is prolonged into a more or less long and slender snout, 
or “ rostrum,” at the end of which the jaws are situated. The number of species already 
known is above 20,000. 
