3160 THE JOINTED ANIMALS 



the sound-producing organs. But if one of them be stripped off, there will be dis- 

 closed a cavity, divided by an oblique horny ridge into two portions, the inner one 

 somewhat irregular in shape, and exhibiting tense glistening membranes in the 

 walls, while the outer portion is narrow and opens by a narrow mouth toward 

 the side. Hidden in the wall of the latter chamber lies the membrane which is 

 the chief organ concerned in the production of sound. These membranes are set in 

 vibration by the contraction and relaxation of a pair of strong muscles attached 

 to their inner faces and lying inside the body. The other membranes in their 

 neighborhood seem to serve the purpose only of modulating the sound. The cicadas 

 figured are two of the commoner species from South Europe. Both live on ash 

 trees, although Cicada orni selects by preference the manna ash. The specimen 

 with its under side exposed may be easily recognized as a male, on account of the two 

 plates, or opercula, covering the cavities in which the sound apparatus is lodged. 

 The lantern flies and other insects included in the family Fulgoridce are char- 

 acterized by never having more than two ocelli, these being placed, one on each side, 

 near the inner margin of the compound eyes. The latter are not large, and below them 

 are inserted the short and inconspicuous antennae. The front, vertex, and sides of 

 the head are usually separated from one another by sharp crests, and the head itself 

 is in some cases greatly prolonged in front. The fore-wings are either similar in 

 texture to the hind pair or else somewhat harder and more leathery. The Chinese 

 lantern fly (Hotinus candelarius} , so widely distributed in Asia, is one of the best 

 known, the common names said to be given to it in China being very suggestive of 

 its luminosity, although so far there is no trustworthy evidence to show that it 

 possesses any such property. Lantern flies are nearly all prettily colored; and of 

 the other insects belonging to the same family there are some, like those of the 

 genus Plata, rivaling in the delicacy of their colors the most beautiful butterflies or 

 flowers; while others, as in the genus Flatoides, exhibit that curious mixture of gray 

 and black, which, in combination with the flattened form of their bodies, gives them 

 the most astonishing resemblance to lichen-covered bark. The species of Plata 

 and other genera are remarkable also for their white tufted tails of wax, which are 

 found more especially in the larvae, but are often present only in the winged insects. 

 These insects do not stir far from their food plant, on which they may be seen both 

 in the larval and adult state, clustered together in large numbers, somewhat after 

 the manner of plant lice. The European species of Fulgorida are not remarkable for 

 their size or the brilliancy of their colors. Issus coleoptratus is perhaps the largest 



British species, and we figure Cixius nervosus, another 

 widely-distributed British and European species, to- 

 gether with Pseudophana europcea, the sole representa- 

 tive in Europe of its genus, and sometimes spoken of as 

 the European lantern fly. 



The frog hoppers (Cercopidce} are mostly small 

 insects with a short broad head and stiff opaque 

 elytra. They usually have two ocelli placed on the 



Cixius nervosus. vertex of the head between the compound eyes; and 



(Enlarged.) their antennae are inserted, not below the eyes as in 



