OR, THE HOME-CULTURE OF FRESH-WATER PLANTS. 



Whirligigs (Gyrinidce), so called from their whirling 

 movements on the surface of the water, where their 

 shining coats of bright bronze have a glittering 

 appearance in the early days of spring. There are 

 also the Water Boatmen (Notonectd) and the Water 

 Scorpion (Nepa), well worthy of a place in the 

 tank. 



There are also the Caddis Worms of different 

 kinds, which form interesting objects, clothed in their 

 portable house of little sticks and stones (see Plate 

 III.), which protects them from the attacks of fish 

 or other insects. They are the larva stages of 

 various species of Phryganea. 



One of the most interesting creatures in a tank 

 is the Diving Spider (Argyroneta aquatica), which, 

 however, should not be placed with fish or voracious 

 beetles, or he would soon disappear. The trans- 

 parent membrane which surrounds the body of the 

 Water Spider, and enables him to swim, gives him 

 the appearance, when in motion, of a globule of 

 quicksilver an appearance which has rendered him 

 a great favourite with keepers of Aquaria. There 

 are other species of Water Spiders, but living upon 

 the surface of the water, and not having the power 

 of diving, they are not so attractive as the silvery, 

 air-clad species. It constructs its nest in a singular 



