TRACHEATA 341 
irritating noise by rubbing the short anterior wings against the 
posterior. As in the preceding family, the auditory organ is 
on the proximal end of the anterior tibia. The tarsus is three- 
jointed. The females are usually provided with a straight 
ovipositor, and the males attach a spermatophore containing 
semen to the genital orifice of the female. 
Gryllus campestris is the field cricket, and G. domesticus the 
house cricket. Gryllotalpa vulgaris, the mole cricket, leads 
mainly a subterranean life; it is of a brown colour, and has its 
two anterior legs short and thick, and adapted for digging. 
The female lays from 200 to 300 eggs in a nest the size of a 
hen’s egg, situated some inches below the surface of the ground. 
The Orthoptera genuina, from their habit of moving in 
immense swarms and devouring all the green parts of plants 
dock lad = 
SRP PTE 
IIo r$ Fee = 
Fic. 193.—Caloptenus italicus. Natural size. 
which come in their way, are Insects of great economic 1m- 
portance. The females usually lay their eggs in waste and 
inaccessible places termed in America “ mauvaises terres” ; the 
young larvae when hatched make their way to more cultivated 
districts. As an example of the enormous number of these 
insects, it may be mentioned that in the spring of 1882 over 
1300 tons of locusts’ eggs were destroyed in the island of 
