INSECTS. 137 
with their ovipositors ; the blades of the latter divide, 
and the egg is forced through this channel into the 
wound. An abnormal growth of wood is formed about it, 
from which in time the perfect insect escapes. 
VALUE.—A decoction of certain galls, with sulphate of iron, forms 
the principal ingredient of ink. 
Ichneumon-F lies 
(Ichneumonidae). — These S 
insects (Fig. 172) are re- 
markable for depositing 
their eggs in other in- 
sects, using for the pur- 
pose a long ovipositor 
that is protected by a. Fic. 172.—Ichneumon-fly, showing 
sheath composed of four mechanism of ovipositor. 
Sstylets. Rhyssa persuaso- 
via bores into solid wood in search of its prey. The 
larva, a soft, footless grub, feeds upon its host, and when 
about to become a pupa 
spins a cocoon, from 
which it escapes in the 
adult form. 
Ants (Formicaria). 
—The ants, in the opin- 
ion of Sir John Lub- 
bock, stand next to man 
in point of intelligence. 
They erect wonderful 
7 dwellings, store up food, 
Fic, 173.—Ant's head and foot. Head: aT€ agriculturists, keep 
4, ¢, eyes; @,a, antenne; m,m,man- and tend their cattle 
dibles; 7, 7, jaws; ¢, tongue. Foot: (Aphide), seem to pos- 
Ss, Spur; ¢, +, comb of spur; /, leg- : 
comb, sess a sign-language, go 
to war in organized bod- 
ies, and in many ways show remarkable intelligence. The 
