COCKROACHES. 



132 



preferred, and the gizzard, although rather small, is thick-walled and well developed. The eggs are 

 deposited by the females in very peculiar hard, horny capsules of an oblong form, rounded at the 

 sides and ends, slightly grooved transversely at the interstices between the contained eggs, and slit 

 along one side, the margins of the slit being finely toothed, with the teeth of one side 

 accurately fitting in between those of the other. The eggs, each of which has its own thin 

 but tough envelope, are placed in a double row within this capsule, arranged side by side iu 

 such a way that one extremity of each egg is directed towards the above-mentioned slit. 

 In this manner the escape of the young insect is facilitated, as it has only to push straight forward, 

 and so out of the slit, after softening a sort of cement, with which the closure of the latter is com- 

 pleted. The number of eggs enclosed in these capsules varies considerably in the different 

 species ; the common Cockroach of our kitchens 

 places sixteen eggs in each capsule, but those of 

 other species contain thirty or even forty eggs. 

 It will be easily understood that such a capsule 

 as this is very much out of proportion to the 

 size of the parent insect, and the females appear 

 to have some difficulty in getting rid of their 

 burthen. They have been observed to run about 

 for a long time, sometimes even for several 

 weeks, with one end of the capsule projecting 

 from the extremity of the abdomen. The 

 newly-hatched young are of a pale colour, but 

 speedily become darker. They are said to 

 change their skin about six times. 



The best-known species is the Common Cock- 

 roach, or " Blackbeetle " (Periplanela orientally), 

 which is not a native of Europe, but is supposed 

 to have been introduced there by commerce from 



COCKKOACHES MALE (A), FEMALE (B), AND YOUNG (c). 



the East. Whatever its origin, however, it has 

 now made a home for itself wherever man dwells. 

 The males have perfect wings and wing-cases, which, however, are shorter than the abdomen ; in 

 the females the tegmina are a pair of small, ovate organs placed behind the prothorax, and the wings 

 are quite rudimentary. Another species, which has attained a distribution almost as wide, though 

 not so general, is the American Cockroach (Perijdaneta americana), a native of the warmer parts 

 of America, whence it has been carried in ships to the ports of nearly all parts of the world. It 

 is a larger and redder species than the common Cockroach, and the tegmina and wings are fully 

 developed, the former passing beyond the extremity of the abdomen. This insect is common on 

 board ship, and may be almost constantly met with in the docks, especially when tropical produce is 

 being landed. It is likely that other species have been similarly transported to new localities, and, 

 indeed, this is known to be the case with a pale species (Panchlora maderce), originally described as a 

 native of Madeira, but now found in Brazil and the East and West Indies, as well as in European 

 ports. 



Besides these undoubtedly introduced exotic forms, we have in Europe a few species which 

 appear to be indigenous, and which, both in Britain and on the Continent, live in the open air, in 

 woods, although they sometimes come into houses, and in some localities do considerable mischief. 

 The best known of these may be called the German Cockroach (Blatta germanica), an insect about 

 half an inch long, of a pale yellowish colour, with two blackish longitudinal bands on the pronotum. 

 The wings and tegmina are well developed. This species is common in many parts of Europe, and in 

 some places it has proved very troublesome in houses, and especially in breweries and distilleries. 

 The insects are supposed by the Russians to have been introduced into their country from Germany, 

 and thence called " Preussen." In Austria they are thought to have come from Russia, and 

 accordingly denominated " Russen." They have also made their way into other countries. Another 

 species of smaller size, which is common in woods on the continent of Europe, and is found in 



