LONDON INSECTS 107 



along in just the same way by squirting through tubes. 

 The principle which had already been applied in the 

 British Navy in the Watevwitch is exactly that of 

 the German invention, and is destined, according to 

 Admiral von Henck, 'to modify, or even supersede, 

 the present ship engines.' The only difference is a 

 trifling one in the application. The valves, instead of 

 being ' amidship,' and ' above the water ' as in the 

 vessel, are in the insect placed at the stern and used 

 under water. 



Dragon -flies of several kinds are occasionally, 

 though not very often, to be seen in London, but we 

 have plenty of other representatives of the ' nerve 

 winged ' order. A very pretty one, with antenna 

 much longer than itself, is to be seen in quantities any 

 warm day in August or September, running about on 

 the flat wooden railing of the bridge across the water 

 in St. James's Park. It is what fly-fishermen know 

 as the ' Cinnamon/ one of the Caddis-flies the family 

 which, in the grub state, live in the water and build 

 themselves quaintly ornamented houses, which they 

 carry about with them. The nerves of the wings 

 of the Cinnamon-fly are almost hidden by brown 

 feathers, but it is still one of the Neuroptera. There 

 are plenty of the Ephemera, too, of which the May- 

 fly is one. May-flies in the perfect state have no 

 visible mouth, and no one yet has been able to dis- 

 cover that they take food or nourishment of any kind, 

 unless it is sucked in with the air through their 

 breathing-tubes. 



