GENERATION OF INS-ECTS. 13 



efygs, or ovula, of innumerable kinds of animalcules 

 floating by myriads of myriads through the atmo- 

 sphere, so diminutive as to bear no larger proportion 

 to the eggs of the aphis than these bear to those of 

 the wren or the hedge-sparrow ; protected at the 

 same time from destruction, by the filmy integument 

 that surrounds them, till they can meet with a proper 

 nest for their reception, and a proper stimulating 

 power to quicken them into life ; and which, with 

 respect to many of them, are only found obvious to the 

 senses in different descriptions of animal fluids*." 



It appears to us that it can be nothing more than 

 a fancy, which is quite unsupported by evidence, to 

 say that the eggs of any species of animalcules or 

 insects float about in the atmosphere; for, inde- 

 pendent of their weight, (every known sjiecies being 

 greatly heavier than air,) the parent insects of every 

 species whose history has been accurately investi- 

 gated, manifest the utmost anxiety to deposit their 

 eggs upon or near the appropriate food of the young. 

 To commit them to the winds would be a complete 

 dereliction of this invariable law of insect economy. 

 But admitting for a moment this hypothesis, that the 

 eggs of insects are diffused through the atmosphere, 

 the circumstance must be accompanied with two 

 conditions, — the eggs must either be dropped by the 

 parents while on the wing, or be carried off by winds 

 from the terrestrial substances upon which they may 

 have been deposited. 



On the supposition that the eggs are dropped by the 



mother insects while on the wing, we must also admit 



(for there is no avoiding it) that they continue to 



; i float about, unhatched, from the end of summer 



I I till the commencement of spring, at which time only 



,, i the broods make t.ljeir appearance. Yet when we 



" * Good's Study of Medicine- vol, i , p. 339, Srd edition, Lon- 

 don, 18^3. 



C 



