378 



SANITARY ENTOMOLOGY 



brown witli tAvo, usually conspicuous, longitudinal, blackish stripes on 

 the pronotum. Both sexes are fully winged, both tegTuina and wings 

 exceeding the tip of the abdomen in both sexes. The male is more slender 

 than the female but the last abdominal segment does not exhibit sexual 

 differences as in the case of the above species. It is a more active insect 

 than orientalis, breeds faster, and is no less prevalent in houses, but, being 

 less restricted to filthy surroundings, is more often found in houses of a 

 better class. But no home, no matter how well kept, is immune from 

 invasion now and then b}- one or more of these roaches, as not a store of 

 food, bundle of laundr}'-, or lot of sujDplies of any kind can be brought 

 in without danger of one or more roaches being introduced. 



This species seldom occurs in company with the oriental roach, a house 

 overrun with one species usually being free from the other. 



Fig. 72. — The German roach, Blattella germanica: a, First stage; b, second stage; c, 

 third stage; d, fourth stage; e, adult; /, adult female with egg case; g, egg case, 

 enlarged; h, adult with wings spread. All natural size except g. (From Riley.) 



Periplaneta americana (Linnaeus) (fig. 73) 



This, the American roach, is less frequently abundant in houses than 

 the smaller forms, at least usually so, though in the warmer parts of 

 the world it is frequently the prevalent household species. It is more 

 frequently reported as doing damage to plants in greenhouses, etc., and 

 very often it creates havoc indoors with books, clothing, and other 

 material. 



This roach is decidedly larger than either of the foregoing species, 

 both sexes being about one and one-half inches in total length, often 

 somewhat longer and rarely as much as a quarter of an inch shorter. 

 Both sexes are fully winged, the wings usually surpassing somewhat the 

 tip of the abdomen. The general color is reddish brown with the pro- 

 notum generally bordered around the disk with lighter yellowish color, 

 usually in distinct contrast to the darker central portion. The ventral 

 surface of the last abdominal segment of the two sexes here differ as in 



