TRACHEATA 365 
the abdomen. These drums are furnished with a curiously 
ribbed surface, and the characteristic noise of the Cicadas is 
said to be produced by the vibrations of the ribs set in 
motion by air forced against them. The females have stout 
ovipositors ; in Cicada septemdecem the females lay their eggs 
in slits which they cut in young twigs, the larva hatches out 
in six weeks, drops to the earth, and buries itself. It remains 
underground till the seventeenth year, when it emerges, be- 
comes adult, pairs, and as soon as the eggs are deposited 
disappears. 
Family FuLGorIpAE—The antennae are bristle-like and 
three-jointed. The insects are very diverse in structure, many 
of them have the most extraordinary outgrowths of the upper 
part of the head. These protuberances may equal in size the 
rest of the insect’s body. Fulgora candelaria and F. lanternaria 
are stated to be phosphorescent, but this appears doubtful. 
Some species excrete wax from their abdomen in such quan- 
tities that they have a commercial value in China. 
Family CERCOPIDAE (Frog-hoppers).—The anterior wings 
of these insects are opaque. Their three-jointed antennae end 
in a bristle. The head is triangular, with two ocelli. <Aphro- 
phora spumaria, the cuckoo-spit, is an insect about + inch 
in length. It can take very extended leaps. Its larva sur- 
rounds itself by a white frothy fluid which it excretes from its 
intestine. It is common in England on leaves of plants, ete., 
in fields. The eggs are deposited in punctures in the leaves. 
Family APHIDIDAE (Plant-lice)—Small insects with oval 
or pear-shaped bodies. The wings, when present, are trans- 
Fie. 205.—Siphonophora 
JTanariva. 
. Winged aphis. 
. Natural size of same. 
3. Wingless form. 
. Natural size of same, 
parent, and with few nervures; the anterior and posterior wing 
of each side are fastened together by a hook. Proboscis two- 
