The Biology of the Roach 61 
Thus we see that their normal time for reaching adult- 
hood covered a period of five weeks (the one straggler 
may reasonably be regarded as abnormal). It is safe 
to regard this as a typical sample under normal condi- 
tions, since the pests always live in houses in similar 
conditions. The proportion of sexes, 47 males to 31 
females, agrees with the condition we almost always find 
in the insect world, i. e., a larger proportion of males. 
ee 
Fig. 1. The cockroach Blatta orientalis. 
Here, too, the mean date of emergence of the males is 
slightly in advance of that of the females. 
On the authority of Riley,* Hyatt says the larvae of 
this species when hatched are brooded over by the 
mother. The mother roaches in my experiments gave no 
evidence of maternal solicitude. In fact, the data here- 
‘Insecta, 1890, p. 103. 
