RHYNCOTA. 35 



the breast. Mr. Westwood divides this sub-order into 

 three sections, according to the number of joints of the 

 tarsi; those insects whose tarsi are three-jointed con- 

 stitute the section Trimera, those with two-jointed 

 tarsi the Dimera, those with one-jointed tarsi the 

 Monomera. 



Of the Trimera, the Cicada is an instance. Theie 

 are many species of this family occurring in different 

 parts of the world, but only one British representative, 

 viz., the Cicada Anglica (see Plate L, Fig. 1). The 

 CicadidiB are the largest insects in the sub-order, some 

 foreign species measuring as much as six and seven 

 inches in expanse of wing. The English Cicada has 

 been occasionally seen in great numbers in the New 

 Forest ; I do not know what other recorded habitats 

 there are. The ovipositor of the Cicada is a remarkable 

 instrument ; it is made of two strong saw-like borers, 

 which work in the grooves of a supporting plate and 

 pierce the wood for the reception of the eggs, which are 

 generally deposited in dead branches, from five to seven 

 hundred in number. But these insects sometimes de- 

 posit their eggs in living branches from which the sap 

 exudes ; thus injuring the trees. Dr. Asa Fitch, a high 

 American authority on all matters relating to insects, 

 includes the G. septemdecim amongst the noxious 

 insects. The species has received its specific name from 

 its supposed periodic visitations every seventeen years. 

 The opinion has been confirmed by Dr. Asa Fitch, who 

 remarks that "the horde of each district probably 

 preserves the interval of seventeen years for coming out 

 in its winged state" (see Report i. and ii., p. 38). The 

 Cicada jplebeia, common in the South of Europe, is 



D 2 



