HOUSEHOLD INSECTS 



91 



is the smallest of the domestic cockroaches and is even more 

 agile than its larger relatives. Like them it is a very general 

 feeder, consuming all sorts of animal matter, cereal products, 

 paste, glue, bread, etc. All of our domestic roaches show 

 their tropical origin in their inability to withstand cold and 

 their occurrence in cooler climates is restricted to heated 

 dwellings. 



Three of our larger roaches are Blatta (Fig. 39), orientalis, 

 the oriental cockroach, Periplaneta australasios, the Aus- 



FIG. 30. One of the larger domesticated cockroaches (Periplaneta). The male, shown at the 

 left, is more slender than the female. Neither of them often remains still long enough for one 

 to observe them closely. 



tralian cockroach and Periplaneta americana, the American 

 cockroach. They are thought to have originated in the 

 orient, in Australia, and in the American tropics respectively, 

 but have been widely distributed for so long that their pro- 

 venience cannot be stated with any great assurance. All are 

 much larger than the Croton bug, especially the Australian 

 and American species, and they do not occur in such abun- 

 dance in cooler regions. They find especially salubrious con- 



