TRACHEATA 341 



imtating 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 



Fig. 193. — Caloptenus italicus. Natural size. 



which come in their way, are Insects of great economic im- 

 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 



