20 THE COCKROACH : 



but have never observed them in my house till lately."* It is 

 probable that many English villages are still clear of the pest. 

 The House Cricket, which the Cockroaches seem destined to 

 supplant, still dwells in our houses, often side by side with its 

 rival, sharing the same warm crannies, and the same food. The 

 other imported species, though there is reason to suppose that 

 they cannot permanently withstand orientals, are by no means 

 beaten out of the field ; they retreat slowly where they retreat 

 at all, and display inferiority chiefly in this, that in countries 

 where both are found, they do not spread, while their competitor 

 does. It may yet require some centuries to settle the petty wars 

 of the Cockroaches. 



It is also worth notice that in this, as in most other cases, the 

 causes of such dominance over the rest as one species enjoys are 

 very hard to discover. We cannot explain what peculiarities 

 enable Cockroaches to invade ground thoroughly occupied by 

 the House Cricket, an insect of quite similar mode of life : 

 and it is equally hard to account for the superiority of orientalis 

 over the other species. It is neither the largest nor the smallest; 

 it is not perceptibly more prolific, or more voracious, or fonder 

 of warmth, or swifter than its rivals, nor is it easy to see how 

 the one conspicuous structural difference viz., the rudimentary 

 state of the wings of the female, can greatly favour orientalis. 

 Some slight advantage seems to lie in characteristics too subtle 

 for our detection or comprehension. 



Food and Habits. 



As to the food of Cockroaches, we can hardly except any 

 animal or vegetable substance from the long list of their depre- 

 dations. Bark, leaves, the pith of living cycads, paper, woollen 

 clothes, sugar, cheese, bread, blacking, oil, lemons, ink, flesh, 

 fish, leather, the dead bodies of other Cockroaches, their own 

 cast skins and empty egg-capsules, all are greedily consumed. 

 Cucumber, too, they will eat, though it disagrees with them 

 horribly. 



In the matter of temperature they are less easy to please. 

 They are extremely fond of warmth, lurking in nooks near the 



* Bell's Edition, Vol. I., p. 454. 



