186 THE CAUSES WHICH PROPAGATE 



This feat of activity accounts for the sudden manner in which 

 they often leave their haunts, as it does for the method by which 

 they come to houses where they were not known before. It is 

 remarkable that many sorts of insects seem never to use their 

 wings but when they have a mind to shift their quarters and 

 settle new colonies. When in the air, they move volatit, tindoso, 

 in waves or curves, like woodpeckers, opening and shutting their 

 wings at every stroke," and so are always rising or sinking. 

 When they increase to a degree, as they did once in the house 

 where I am now writing, they become noisome pests, flying into 

 the candles, and dashing into people^'s faces/'' 



When the male sings he elevates the wing-covers so as to 

 form an angle with the body, and then rubs them against 

 each other by a horizontal and very brisk motion. The music 

 is capable of considerable modulation, and as in the case of the 

 Leaf -crickets, the chirps come quicker and angrily when male 

 meets male, especially if a female, the object of all dispute, be 

 present. For though from a distance the note falls on the ear 

 with a monotonous sound of " Cree-cree ! " if the observer will 

 station himself near the hearth when these insects are briskly 

 stridulating on a frosty morning, at which time the air is espe- 

 cially sound-transparent, and they most noisy, two notes may be 

 distinguished — a loud "■ Awhit ! awhit ! awhit ! " uttered in unison 

 with the ticks of the clock, and a lower occasional " Wee, wee ! " 

 uttered hastily, I presume, wdien Greek meets Greek. There is 

 also an alarm-note, " Chreek ! " at which it is said all scamper 

 to their retreats. If the wanton sounds of the male should 

 allure a female, she intimates her presence with her long 

 feelers, and the two engage in antennal discourse ; but tempers 

 are quick in crickets, and the crannies where they lurk 

 become sad dens of cannibalism, since the males, females, and 

 immature pupse alike bite and devour one another, although their 

 rapacity is probably mitigated by the provision of music and 

 their proverbial nimbleness. 



The third indigenous Gryllm, the Little Wood-cricket, has 

 the musical mechanism as before, but differs in that the right 

 wing-ease has a firmer consistence than the left ; so that whereas 

 the former species, in singing, rub the elytra together with 

 either uppermost, and even change them during stridulation. 



