London Insects. 159 



towards the end of the brilliant passage with which 

 he sums up the teaching of his lectures on the 

 " Generation of Insects," it shows how much, if only 

 one knew how to do it, is to be done with London 

 materials. 



"Metropolitan duties," he says, "shut out much 

 of the field of Nature ; but still she may be found 

 and studied everywhere. I first learned to appre- 

 ciate the true nature and relations of the nominally 

 various and distinct metamorphosis of insects by 

 watching and pondering over the development of a 

 Cockroach." 



There are only two more of the orders named to 

 which our claim as Londoners has to be made good : 

 the " nerved wings " and " screw wings." 



The latter are microscopic insects which live during 

 part of their lives as Parasites on Bees. As we have 

 plenty of Bees we have probably also plenty of the 

 insects which live upon them. But as without very 

 good eyes and very good glasses, and time and 

 patience to use them, we are not very likely to find 

 any " screw wings," it is not necessary to say much 

 about them here. Their chief point of interest is that 

 exactly reversing the arrangements of the "two 

 winged" order, their upper instead of their lower 

 pairs of wings are shrivelled up and apparently use- 

 less. The last remaining order the " nerved winged " 

 is of far more general interest, and contains in the 

 Dragon Flies examples of the most perfect develop- 

 ment of powers of flight known, compared with which 

 the wings of a bird are clumsy contrivances. 



The bodies of men and other terrestrial animals 

 are comparatively solid masses. Weight is no dis- 

 advantage to them. If anything, it is an advantage, 

 as it helps them to force their way through the 



