ROACHES AND OTHER ANCIENT INSECTS 



ended only when the last of the brood had been devoured. 

 The mother roach was not at the time molested, but next 

 morning she lay dead on her back, her head severed and 

 dragged some distance from the 

 body, which was sucked dry of 

 its juices — mute evidence of the 

 tragedy that had befallen some- 

 time in the night, probably when 

 the pangs of returning hunger 

 stirred the centipede to renewed 

 activity. The house centipede 

 does not confine itself to a diet of 

 live roaches, for it will eat almost 

 any kind of food, but it is never 

 a pest of the household larder. 



Most species of roaches have 

 two pairs of well-developed 

 wings, which they ordinarily keep 

 folded over the back, for in their 

 usual pursuits the domestic spe- 

 cies do not often fly, except oc- 

 casionally when hard pressed to 

 avoid capture. The front wings 

 are longer and thicker than the 

 hind wings, and are laid over the 

 latter, which are thin and folded 

 fanwise when not in use. In these 

 characters the roaches resemble 

 the grasshoppers and katydids, 

 and their family, the Blattidae, is 

 usually placed with these insects in the order Orthoptera. 



The wings of insects are interesting objects to study. 

 When spread out flat, as are those of the roach shown in 

 Figure 53, they are seen to consist of a thin membranous 

 tissue strengthened by many branching ribs, or veins, 

 extending outward from the base. The wings of all insects 

 are constructed on the same general plan and have the 



[83] 



Fig. 52. The common house 



centipede, Sctttigera forceps 



{natural size), a destroyer of 



young roaches 



