ENTOMOLOGY

COCKROACHES 379the case of Blatta orientalis, being plane in the male and longitudinallydivided in the female.This species is thoroughly cosmopolitan in distribution, having beenrecorded from almost every portion of the world except the colder regions.In some sections it is the most common house species, though in the easternUnited States it is not usually so common as either of the smallerspecies 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 andcovered over with particles che'Yed off by the insect. The egg-cases ofFIG. 73.-The American roach, Pe1iplaneta Americana: a, View from above; b, frombeneath. Enlarged one-third. (Marlatt.)americana have been found, by actual count, to vary considerably in thenumber of eggs contained, the average, however, being about a score.The adult insect lives well over a year, one in captivity having died onlyafter a confin_ement of one and one-third years. .Nothing is inviolable to injury by this large roach, and it, as well asother forms discussed here, will even eat its own eggs, or a disabled individualof its own kind, to say nothing of other insects, even the i11-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 speciesindigenous to the New World, its original home probably b€ing TropicalAmerica.