132 HOUSEHOLD INSECTS 



THE LIFE HISTORY OF COCKROACHES 



It is almost an axiom that something unknown remains 

 to be found out about almost any insect. This is certainly 

 true of the life history of cockroaches. Many guesses 

 and astonishing statements have been made regarding the 

 time it takes young cockroaches to reach maturity. It 

 has been said that four or five years are required for some 

 species to pass through their life history from the egg to the 

 adult. We cannot flatly dispute this statement, but with 

 one or two species, at least, we know that the time for this 

 development is much less. 



Cockroaches have a peculiar and characteristic habit of 

 depositing their eggs. Instead of laying their eggs one at 



a time, like other insects, they deposit 

 them in batches. The eggs are held 

 within the body of the insects and 



F Troton-b^ Egg c C x3 e ) 0f mc l° se d m a sort °f capsule or egg- 

 case, known as an ootheca (Fig. 37). 

 While in the body of the female the egg-case apparently 

 occupies most of the space within the abdomen. The 

 capsule is more or less bean-shaped and, in case of the 

 Oriental roach, contains just sixteen eggs arranged in 

 two rows. The eggs are more or less outlined within 

 the egg-case by line-like depressions between them. 

 When the egg-case is first deposited it is creamy white in 

 color, but within two or three days it turns to a dark 

 brown nearly like the body of the parent. No very exact 

 observations are known to the author which determine 

 definitely the number of eggs laid by one female roach ; 

 but Seiss confined three females of the Oriental cockroach 

 and observed them to deposit twenty-five cases, an 



