266 



AN INTRODUCTION TO ENTOMOLOGY 



D. Margin of the pronotum light in color while the disk is dark. . . 



The common wood-cockroach, male 



DD. Pronotum reddish-brown with two blotches of a lighter color. 



The American cockroach 



BB. Wings not extending to the tip of the abdomen. 



C. With a light band on each lateral border of the pronotum 



The common wood-cockroach, female 



CC. With no bands on the pronotum The Oriental cockroach, male 



AA. Tegmina represented by small ovate pads The Oriental cockroach, 



female 



The Croton-bug, Blatlella germanica (Fig. 302), is the best-known 

 of all of the cockroaches in our northern cities. It is easily recognized 



by its small size, about 

 4L .-*'*^^ "\ ^ — -^ 12 mm. in length, and 



^ by its pale color with 



two dark, parallel 

 bands on the prono- 

 tum. Its popular 

 name originated in 

 New York City, and 

 was suggested by the 

 fact that this pest is 

 -^ \/ very abundant, in 



^ ^ >*■ houses, about water 



pipes connected with 

 the Croton Aqueduct. 

 This is a species intro- 

 duced from Europe; 

 it has spread to nearly 

 ^ , « all parts of the world, 



living upon ships, and 

 Fig- 303- — The oriental cockroach: a, female; b, spreading from them, 

 male, c side view of female; d, half-grown sped- 'p^e oriental cock- 



men. All natural size. (From Howard and Mar- i, r?;^j. • ,-i- 



J^^l- \ roach, Blatta onentaUs 



(Fig. 303), is also a 

 cosmopolitan species ; its original habitat is supposed to have been 

 in Asia; but it has been distributed by commerce throughout the 

 world except in the colder regions. In this coimtry it is most abun- 

 dant in the central latitudes of the United States ; it has been f otmd 

 in only a few places in Canada. It measures from 18 to 25 mm. in 

 length. It is blackish browTi in color. In the male the wings cover 

 about two-thirds of the abdomen; while in the female they are small, 

 ovate-lanceolate, lateral pads. 



The American cockroach, Periplaneta americdna (Fig. 304), is a 

 native of tropical or subtropical America that has become distributed 

 both in tropical and mild climates over the entire world. This is a 

 large species measuring from 25 to 33 mm. in length. 



The common wood-cockroach, Parcohldtta pennsylvdnica, is a 

 common species throughout the eastern half of the United States, 



