THE HOUSE-CRICKET 179 



themselves clean, combing all parts of their bodies with 

 their legs, and often passing the legs and antennae through 

 the mouth. 



Hardly any insects are known from so remote an antiquity 

 as cockroaches. Many species, not unlike those which haunt 

 our kitchens, have been found in the Coal Measures. 



THE HOUSE-CRICKET {Gryllus domesticus) 



Examine a number of captured house-crickets, and begin 

 by learning how to distinguish the males from the females. 

 The most obvious difference lies in the ovipositor of the 

 female, which is long and slender ; it may be recognised 

 by being apparently single, while the other projections from 

 the extremity of the abdomen are paired. Then remark the 

 obvious differences between the fore wings (wing-covers) of 

 the two sexes. 



The female house-cricket is two-thirds of an inch or more 

 in length (16-21 mm.), the male rather smaller (15-20 mm.). 

 The colour is brown and yellow. The broad head has 

 two transverse bands of yellow, and from it spring the long, 

 slender, many-jointed feelers (antennae). The prothorax is 

 square, as seen from above. Both fore and hind wings are 

 well developed in both sexes. In the female the fore wings 

 (wing-covers) are generally similar to those of the male 

 cockroach ; both are covered with a rather close reticulation 

 of veins ; the hind wings are long and folded fanwise ; when 

 at rest they form two long slender projections, which may 

 be taken at first sight for tail-like abdominal appendages. 

 In the male the wing-covers exhibit a very different pattern, 

 the inner two-thirds being more transparent and marked with 

 few veins. The wings, both of the male and the female, 

 are closely fitted to the body when at rest, lying flat on the 

 back and bending downwards on the sides, nearly at a right 

 angle; the junction of the two surfaces shows conspicuous 

 longitudinal veins and a prominent edge. The legs in both 

 sexes are strong; the hind pair have the thighs thickened 

 for leaping, and the shins (tibia) are armed with strong spines ; 

 there is a three-jointed tarsus to each. On the fore tibia it 

 is not hard to discover with a microscope or strong pocket- 



