COCKROACHES 



379 



the case of Blatta orientalis, being plane in the male and longitudinally 

 divided in the female. 



This species is thoroughly cosmopolitan in distribution, having been 

 recorded from almost every portion of the world except the colder regions. 

 In some sections it is the most common house species, though in the east- 

 ern United States it is not usually so common as either of the smaller 

 species discussed above. 



As stated in the first part of this paper, the egg-cases of Periplaneta, 

 the exact species not determined, are glued to various substances and 

 covered over with particles chewed off by the insect. The egg-cases of 



Fig. 73. — The American roach, Periplaneta Americana: a, View from above; b, from 

 beneath. Enlarged one-third. (Marlatt.) 



americana have been found, by actual count, to vary considerably in the 

 number of eggs contained, the average, however, being about a score. 

 The adult insect lives well over a year, one in captivity having died only 

 after a confinement of one and one-third years. 



Nothing is inviolable to injury by this large roach, and it, as well as 

 other forms discussed here, will even eat its own eggs, or a disabled indi- 

 vidual of its own kind, to say nothing of other insects, even the ill- 

 smelling bedbug. This species is often reported as damaging living plants, 

 a thing seldom charged to the account of the smaller roaches. 



Periplaneta americana is the only one of our common house species 

 indigenous to the New World, its original home probably being Tropical 

 America. 



