518 Mr. Rennie on the Contrivances 



serve the purpose of a thermometer. Sir Edward King, an 

 excellent naturalist, who lived in the time of King Charles II., 

 seems to have been the first to discover this peculiarity : 

 ' I have observed,' says he, ' in summer, that in the morning 

 they bring up those of their young, called ants-eggs (cocoons), 

 towards the top of the bank, so that you may, from ten o'clock 

 till five or six in the afternoon, find them near the top, for the 

 most part on the south side. But towards seven or eight at 

 night, if it be cool, or likely to rain, you may dig a foot deep 

 before you can find them *.' Ants, during winter, unques- 

 tionably manifest more intelligence, instinct, or whatever it 

 may be termed, than bees ; for the hive-bee will rashly venture 

 abroad on the occurrence of a mild day, or even of a few 

 hours' warm sunshine, when the ground is covered with snow ; 

 but I have never observed ants, either in the colonies naturally 

 established, nor in the artificial formicaries that I have kept, 

 tempted to venture abroad before the return of spring. The 

 result is, that the bees (foolish in this instance, though wise in 

 so many others) frequently perish from their rashness ; while 

 the ants are snug in their cells. This is the more surprising, 

 that in the instance of swarming bees appear to be uniformly 

 regulated by the temperature of the weather, and will not 

 leave the original colony when the air is below a certain 

 degree. 



While I was concluding this paragraph, I was, by accident, 

 furnished with an example of the contrivances in question in a 

 well known insect the flea (Pulex irritans), which chanced 

 to leap upon my paper, and, as I took care not to disturb it, I 

 observed it attempting to dig a burrow with its beak. To this 

 task, I have no doubt, it was sufficiently equal; but after 

 working into the paper, so as to make a perceptible hole, it 

 abandoned the spot, as if it did not like the material. After 

 skipping about for some time, it settled on the green cloth 

 cover of my desk, where it again made an attempt to burrow ; 

 and I remarked that, in this case, contrary to its mode of 

 working on the paper, it threw itself on its back, pushing the 

 wool upwards with its feet, and downwards with its shoulders, 



* Phil. Trans. No. xxiii. p. 425-7. 



