122 



NATURAL HISTORY. 



being thus pushed out of sight, and the labium appearing to be two-lobed in front ; in those with a 

 slender galea, the four lobes of the labium are visible. The legs of the first pair are sometimes 

 converted into fossorial organs, sometimes adapted only for walking or running ; and those of the hind 

 pair are generally less elongated than in the succeeding families ; the tarsi are generally of three 

 joints, sometimes fewei'. The fore wings, or tegmina, lie horizontally upon the back of the abdomen, 

 covering each other more or less towards the base, and usually have a sort of fold at the outer margin, 

 by which they embrace the sides of the abdomen ; the wings, which are ample, can be folded into a 

 very small compass, but the extremity of the anterior part of them, which is often marked off from 

 the rest of the wing, is gathered or twisted into a sort of tail, which projects beyond the tegmina and 

 the end of the abdomen. The wings are rarely wanting. The abdomen itself shows nine distinct 

 dorsal and eight ventral half segments, and at its extremity a pair of long, many-jointed cerci. The 

 females of some genera also possess a long, slender, cylindrical ovipositor, which has a slight swelling 

 at its extremity. A curious fact relating to these insects is that the fecundation of the females is 

 effected by the agency of spermatophores of peculiar construction. 



As most people are aware, by their experience of the common House Cricket, the males of these 

 animals ai - e endowed with an uncommon power of noise-making. The stridulation in the case of all 

 the musical species of this family is effected by the rubbing of the tegmina over one another, in a 



manner so well described 

 by Professor Westwood, 

 that we cannot do better 

 than borrow his words. 

 He says " In the males 

 of the House and Field 

 Crickets, on the internal 

 margin, about one-third 

 of its length from the 

 base, a thickened point 

 is observed, from whence 

 several strong veins 

 divei'ge, forming an angle 

 from this point. The 

 strongest of these veins, 

 which runs towai'ds the 

 base of the left wing- 

 cover, is found on the 

 under side to be regu- 

 larly notched trans- 

 versely, like a file ; when 



the wing-covers are closed, this oblique base of the wing-cover lies upon the upper surface of the 

 corresponding part of the right wing-cover ; and when a tremulous motion is imparted to the wing- 

 covers, this bar rubs against the corresponding bar of the right wing-cover, and thus produces 

 a vibration, which is communicated to the other parts of the wing-covers, which, being divided into 

 a number of irregular spaces, have each a distinct vibration, and produce a separate sound," the com- 

 bination of which produces the well-known stridulation. During this operation the wing-covers of 

 the male Cricket are considerably raised, and the insect presents a very remarkable appearance. 



The members of this family are not very numerous, but they occur in all the warmer and 

 temperate parts of the earth ; and although in hot countries the species are certainly more numerous, 

 they are not generally distinguished from their relatives living in colder zones by larger size or finer 

 colours. In fact, as the species ai'e all more or less subterranean in their habits, and nocturnal 

 in their activity, brilliant colouring is not to be expected in them, and they generally exhibit various 

 shades of brown merging into absolute blackness, but some species show brownish-red or orange 

 patches upon their tegmina. They appear to be tolerably omnivorous, feeding both upon animal and 

 vegetable substances, although usually showing a preference for the former ; and the gizzard is well 



METAMORPHOSES OF GRYLLUS CAMPESTRI8. 



