INDIRECT INJURIES CAUSED BY INSECTS. 239 



of merchandize to dust without altering their appear- 

 ance, so that the mischief is not perceived till they 

 come to be handled a . If we make some deduction from 

 this account for exaggeration, still the amount of damage 

 will be very considerable. 



There are three kinds of insects better known, to 

 whose ravages, as most prominent and celebrated, I 

 shall last call your attention. The insects I mean are 

 the cock-roach {Blatta orientalis, L.), the house-cricket 

 {Acheta domestica, F.), and the various species of white 

 ants (Tennes, L.). The last of these, most fortunately 

 for us, are not yet naturalized. 



The cock-roaches hate the light, at least the kind that 

 is most abundant in Britain, (for B. germanica, which 

 abounds in some houses, is bolder, making its appear- 

 ance in the day, and running up the walls and over the 

 tables, to the great annoyance of the inhabitants,) and 

 never come forth from their hiding-places till the lights 

 are removed or extinguished. In the London houses, 

 especially on the ground-floor, they are most abundant, 

 and consume every thing they can find, flour, bread, 

 meat, clothes, and even shoes b . As soon as light, na- 

 tural or artificial, re-appears, they all scamper off as fast 

 as they can, and vanish in an instant. These pests are 

 not indigenous here, and perhaps no where in Europe, 

 but are one of the evils which commerce has imported : 

 and we may think ourselves well off that others of the 

 larger species of the genus have not been introduced 

 in the same way — as, for instance, Blatta gigantea, a 

 native of Asia, Africa, and America, many times the size 

 of the common one, — which, not content with devouring 

 a Ulloa, i. 67. b Annan. Acad, iii. 345. 



