GENERATION OF INSECTS. 15 



of carryino: off the eg-g-s, as they are laid, to the 

 nurseries. The extraordinary labour which this re- 

 quires ill the community may be understood, when, 

 according" to Smeathman, she lays 60 eggs in a 

 minute, which will amount to 86,400 in a day, and 

 31,536,000 in a year. The exceptions now men- 

 tioned, however, do not in the least invalidate on*" 

 general position. 



Cell of a queen of the Termites bclhcosi, uroKcn open in front , 

 the labourers surrounding thu queen and carrying off her eggs. 



Another no less remarkable circumstance is the 

 great weight, or specific gravity, of the egg-s of in- 

 sects. From numerous experiments we may venture 

 to say that those of all the species which we have 

 tried sink rapidly in water the moment they are 

 thrown into it, from the egg of the drinker moth 

 {Odonestis Potatoria^ Germar), which is nearly as 

 large as a hemp-seed, to that of the rose-plant louse 

 {Aphis ros(E), which is so small as to be barely visible 

 to the naked eye. Some eggs of the gipsy moth 

 {Ilypogyrnna dispar, Stephens), indeed, floated in 

 water, because they were covered vvith down. It is 

 well known, as we shall presently show, that the dif- 

 fusion of many of the seeds of plants is accomplished 

 by the winged down with which they are clothed ; 



c2 



