HOUSEHOLD INSECTS 259 



to see this odious insect in order to detect its presence, for 

 it scents the atmosphere of its haunts with a peculiar, 

 characteristic, and unforgettable odour. The insect has 

 been rightly termed disgusting, for it is unclean of habit, 

 soiling everything with which it comes in contact, and not 

 too particular in its choice of food, consuming garbage as 

 readily as the choicest morsels, often falling to leather, 

 blacking, and even its own sick relatives ; on occasion it is 

 as persistent as the house fly in seeking out the family 

 larder, and crawling, as it does in its hundreds, over any 

 eatables that are left uncovered, it quickly renders them 

 inedible. 



But though an insect to be rigorously excluded from 

 man's dwellings, its life-history is of peculiar interest. 

 The adult males and females may be readily distinguished ; 

 the former are winged, whilst the latter possess, at most, 

 the rudiments of wings. The males too are smaller than 

 their partners, and, quite apart from structural differences, 

 the sexes may be distinguished from the fact that the 

 females drag their abdomens along the ground, whilst the 

 healthy males never do so, but lift them up an appreciable 

 distance from the surface over which they are crawling. 



The females, like some other members of the Orthoptera, 

 do not lay their eggs singly or even in clusters, but in neat 

 purse-like cases each containing sixteen eggs. These egg 

 cases (fig. 70) are about half an inch long, dark brown in 

 colour, and of a horny texture ; oblong in shape, they have 

 rounded ends, and the upper edge appears as a longitudinal, 

 toothed ridge, which in reality is a slit, kept closed by the 

 elasticity of the material composing the egg case. The 

 eggs within the case are arranged in two alternating rows 

 of eight each, in such a manner that the heads of the larvae 

 are directed towards the serrated edge. When the egg 

 case is full it is carried about by the female, partially 

 protruding from the end of her abdomen, for a considerable 

 time, often as long as a week, and not until she finds a 



