ORGANS OF REPRODUCTION. 83 



has ample wings, when the female has none, or very 

 minute ones, not adapted for flying. 



The Vapourer moth, the female with plain ears and with very 

 short wings ; the male with feathered ears and large wings. 



The male insects are, in most cases, more restless 

 and wandering than the females, and of course more 

 frequently seen, differing in this from spiders, the 

 males of which are seldom or rarely seen. 



All female insects have eggs, which, in a few cases, 

 are hatched within the body, but are generally laid in 

 such places as the young may readily find food when 

 hatched; the mother, in most instances, dying soon 

 after the laying, and of course the young have from 

 the first to shift for themselves. 



These are ascertained facts which cannot be ques- 

 tioned, though they do not accord with the popular 

 error of insects being generated by putrefaction, and 

 by blighting fogs or winds, much less the so-called 

 philosophical theory of their being generated by some 

 sort of mysterious chemistry. 



This theory was supposed to be unanswerably sup- 

 ported by the multiplication of microscopic animal- 

 cules in water, which could not, on account of their 

 minuteness, be traced to their parents. This, however, 

 though apparently impossible, has recently been done 

 by Professor Ehrenberg of Berlin, who, by putting 

 the animalcules in coloured fluids, succeeded not only 

 in discovering their eggs and the hatching of these 



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