OBSERVATIONS ON INSECTS AND VERMES. 407 



BLATTA ORIENTALIS.-COCKROACH. 



A neighbour complained that her house was overrun with a kind 

 of blackbeetle, or, as she expressed herself, with a kind of black- 

 bob, which swarmed in her kitchen when they got up in a morning 

 before daybreak. 



Soon after this account I observed an unusual insect in one of 

 my dark chimney closets, and find since, that in the night they swarm 

 also in my kitchen. On examination I soon ascertained the species 

 to be the Blatta orientalis of Linnaeus, and the Blatta molendinaria 

 of Mouffet. The male is winged ; the female is not, but shows 

 somewhat like the rudiments of wings, as if in the pupa state. 



These insects belonged originally to the warmer parts of America, 

 and were conveyed from thence by shipping to the East Indies ; and 

 by means of commerce begin to prevail in the more northern parts 

 of Europe, as Russia, Sweden, &c. How long they have abounded 

 in England I cannot say ; but have never observed them in my 

 house till lately. 



They love warmth, and haunt chimney closets and the backs of 

 ovens. Poda says that these and house-crickets will not associate 

 together ; but he is mistaken in that assertion, as Linnaeus suspected 

 he was. They are altogether night insects, (Lu<*/uga\ never coming 

 forth till the rooms are dark and still, and escaping away nimbly at 

 the approach of a candle. Their antennae are remarkably long, 

 slender, and flexile. 



October, 1790. After the servants are gone to bed the kitchen 

 hearth swarms with young crickets and young BlattcE molendinaria 

 of all sizes, from the most minute growth to their full proportions- 

 They seem to live in a friendly manner together, and not to prey 

 the one on the other. 



August, 1792. After the destruction of many thousands of Blattce 

 molendinaricB) we find that at intervals a fresh detachment of old 

 ones arrives, and particularly during this hot season ; for the 

 windows being left open in the evenings, the males come flying in at 

 the casements from the neighbouring houses, which swarm with 

 them. How the females, that seem to have no perfect wings that 

 they can use, can contrive to get from house to house does not so 

 readily appear. These, like many insects, when they find their 

 present abodes overstocked, have powers of migrating to fresh 



