RHYXCOTA. 
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 Dimer a , those with one-jointed tarsi the 
Monomer a. 
Of the Trimera, the Cicada is an instance. There 
are many species of this family occurring in different 
parts of the world, but only one British representative, 
viz., the Cicada Anglica (see Plate I., Fig. 1). The 
Cicadidce 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- 
j)Osit 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 C. 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 plebeia , common in the South of Europe, is 
D 2 
