THE COCKROACH 177 



and tussock, he found that the smallest length of the forceps 

 of the male was as low as 2.5 mm., the greatest as high as 

 9 mm. ; the forceps of the female scarcely varied at all. 

 But for the occurrence of intermediate individuals, the males 

 would have been considered to belong to distinct species ; 

 indeed the males with long forceps have been so separated, 

 though afterwards reunited with the common form.* 



Earwigs are mostly shy insects, coming out chiefly by night, 

 and hiding during the day. under stones or in crevices. They 

 feed mainly upon decomposing vegetable or animal matter, 

 but will occasionally devour fresh tissues. They propagate 

 in autumn, having then recently come to maturity, and lay 

 eggs at short intervals from November to early spring; the 

 males do not outlast the depth of winter, and their dead 

 bodies are often found in the winter retreats of the females. 

 The female, watches and defends her young and eggs — an 

 uncommon thing in insects, though frequent among spiders. 

 The embryo is provided with a frontal spine for breaking 

 the egg-shell ; after the first larval skin is cast, which happens 

 immediately after hatching, the spine is lost. The parent 

 dies in spring, before her brood reaches maturity. 



The life-history of earwigs is similar to that of other 

 Orthoptera. The young from the first resemble the parent, 

 but have no wings, which subsequently develop externally 

 and by gradual increase. There is no resting stage. The 

 wing-peculiarities are hardly sufficient to justify the separation 

 of the earwigs from the Orthoptera, particularly since one 

 of the most marked of them — viz. the mode of folding — is 

 paralleled in some cockroaches. 



THE COCKROACH (Periplaneta orientalis) 



The external form and some points in the anatomy of the 

 cockroach have been described in Lessons 2, 3 and 4, so that 

 we shall now only give a short description of its mode of life. 



The common cockroach of our kitchens is not truly a native 

 of Britain ; it is indigenous to the hot countries of the East, 

 and, taking advantage of the facilities afforded by commerce, 

 has gradually made its way into various lands distant from 



* Bateson, " Materials for the Study of Variation," p. 40. 

 M 



