OBSERVATIONS ON INSECTS. 309 



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, ludfugce, 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 blatta 

 molendinarice 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 

 bfattce molendinar'uE) we find that at intervals a fresh detach- 

 ment 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 over- 

 stocked, have powers of migrating to fresh quarters. Since 

 the blattcz have been so much kept under, the crickets have 

 greatly increased in number 



GRYLLUS DOMESTICUS, (HOUSE-CRICKET.) November. 

 After the servants are gone to bed, the kitchen hearth swarms 

 with minute crickets not so large as fleas, which must have 

 been lately hatched. So that these domestic insects, cherished 

 by the influence of a constant large fire, regard not the season 

 of the year, but produce their young at a time when their 



* Although the cockroach is generally to be seen only on leaving its 

 retreat after sunset, yet they occasionally do appear through the day. 

 Our friend, Sir Patrick Walker, who is an excellent practical naturalist, 

 and well skilled in entomology, informed us, that the captain of a vessel 

 from the Mauritius told him, that during their passage from thence to 

 Leith, cockroaches used simultaneously to come on deck, from the hold, 

 which was infested with them, and take to their wings in myriads, fly 

 several times round the vessel like a dense cloud, alight on the deck, ancl 

 instantly retreat below. ED. 



