76 APPLIED ENTOMOLOGY 



Family Blattidae (The Roaches) 



These insects are known by a variety of common names such as 

 roaches, cockroaches, water-bugs, and black-beetles. The group is 

 primarily one living in warm countries with many kinds living in houses, 

 and many more, some of them several inches in length, occurring wild. 

 In more northern climates only a few are wild and four are household 

 pests; these last when adult ranging from less than an inch to nearly 

 two inches in length. In the north the wild species are found under 

 logs and stones and never enter houses. They are pale brown and the 

 winged adults are an inch or slightly more in length. 



Roaches are generally brown or dark colored, though some are 

 green. They are broad and flattened, with the head bent under the body 

 so that the mouth opens backward and the eyes look downward. The 

 antennae are long, slender and of many segments. Wings are usually 

 developed in the adults and the hinder pair fold once. The mouth 

 parts are strong and the legs are long, and bear many spines. Roaches 

 are active at night, hiding in dark places such as cracks and crevices 

 during daylight, and can run rapidly. 



FIG. 45. Egg case of American Roach: a, side; b, end view. Both considerably enlarged. 

 (Modified from U. S. D. A. Farm. Bull. 658.) 



The household pests of this group consume foods and food materials 

 freely; gnaw woolen goods, leather, and anything which has paste 

 on it, and thus often injure book bindings; in fact they are practically 

 omnivorous. Besides eating, they leave a disagreeable "roachy" odor 

 which spoils food where they have been. When abundant they become 

 very troublesome and vigorous measures must be taken for their control. 

 They lay their eggs in packets, the number per packet varying with the 

 species, and the outside case is horny in nature (Fig. 45). This case 

 may be carried around partly projecting from the body of the parent for 

 several days or even weeks. The young are active, feed freely and molt 

 several times, but it is doubtful if there is more than one generation a 

 year, at least in the northern United States. 



HOUSE ROACHES 



The German Roach (Blatella germanica L.). This insect, often 

 called the Croton bug, came from Europe and is generally the most 

 common of the house roaches in the eastern United States (Fig. 46). 



