TRACHEA TA 



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 Fulgoeidae. — 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 Ceecopidae (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, etc., 

 in fields. The .eggs are deposited in punctures in the leaves. 



FamUy Aphididae (Plant-lice). — Small insects with oval 

 or pear-shaped bodies. The wings, when present, are trans- 



Pie. 205. — SipJwnophora 

 granaria. 



1 . Winged apWs. 



2. Natural size of same. 



3. Wingless form. 



4. 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- 



