HOUSEHOLD INSECTS 265 



and rubs the fore wings over one another rapidly ; the under 

 surfaces of the veins are rigid and file-like, so that, as they 

 rub against the veins of the other wing, they produce 

 squeaking sounds which the clear areas or " drums " render 

 more audible. 



Why, it may be asked, does the cricket make the chirp- 

 ing noise ? It is undoubtedly a signal to others of its kind 

 and especially females. A close examination of the outside 

 of the cricket's foreleg, on the part just below the thigh, 

 will reveal an oval membranous portion, and, at the same 

 point, on the inner surface of the leg, a round membranous 

 portion ; between these two membranes is an air sac, con- 

 nected with a breathing tube and well supplied with nerves. 

 These peculiar organs of the forelegs are the ears or 

 auditory organs of the cricket. 



The life-history of this cricket is so similar to that of 

 the cockroach that there is no need to describe it. The 

 young arising from the eggs are very similar to, though 

 smaller than, the parents, and they reach the adult stage 

 by a series of moults, at the final one of which they attain 

 their wings. Their food consists of all kinds of odd scraps, 

 for the most part of a vegetable nature, and they are 

 also moisture- and heat-loving creatures. Whence they 

 came originally is unknown, but now they are not only 

 widely distributed in the Old World, but in North America 

 as well. Britain boasts four representatives of the family : 

 two field-crickets, Nemobius sylvestris and Acheta cam- 

 pestris, the mole-cricket, Gryllotalpa vulgaris, and the 

 house-cricket ; and of these the house-cricket, at any rate, 

 is steadily becoming rarer in Britain. 



Of the common British earwig, Forficula auricularia, 

 little need be said ; it is not a true household insect, though a 

 very frequent intruder. Its general appearance is known 

 to everyone in Europe, where, in each country, its popular 

 name is associated with the ear, and is derived perhaps 

 from the scientific name of the species, or from its supposed 



