72 MICROSCOPIC ILLUSTRATIONS. 



of food in the immediate neighbourhood of the nest, they 

 may be seen to attack and devour each other. 



These larvae, as well as most of those of the larger 

 kind, are found at a greater depth of water than are the 

 smaller ones ; although, in their pursuit of small prey, 

 they may occasionally be taken in shallow places. They 

 require a larger net to collect them with. A net made of 

 stout Irish linen, about a yard deep, and affixed to a 

 hoop half a yard in diameter, will answer the purpose 

 very well ; and if it be attached to a long stick, the 

 collector will be enabled to use it with greater facility. 



In its infant state, this larva is very transparent ; hence 

 its internal structure may be clearly distinguished. 



When about a quarter of an inch in length, it swims 

 very nimbly. The colour of the head is a strong Indian 

 yellow, with darker shadings of a bright chestnut; the 

 eyes are now bright carmine. It is more sparingly 

 covered with hairs, and its swimming appendages are 

 shorter than at a more advanced period ; and the head is 

 larger, in proportionate the size of the body, than when 

 the creature has arrived at maturity. In this respect it 

 resembles many other creatures in its mode of growth, 

 the head seeming to be developed and perfected before 

 the rest of the system. 



When young, it may be readily preserved in gum- 

 water, in the manner described in the " Microscopic 

 Cabinet," p. 229. I have several of them mounted in 

 this way, varying in size from one-tenth to half an inch 

 in length ; and although nearly eight years have elapsed 



