60 MICROSCOPIC ILLUSTRATIONS. 



(juented spot, where she may deposit them free from 

 danger. This is probably the cause why this larva is dis- 

 covered with so much difficulty ; the collector being 

 seldom able to procure it two seasons consecutively in the 

 same place. 



The vignette at the head of this chapter was drawn 

 from a specimen bred in a vase. Whilst in the act of 

 producing the cluster of eggs figured on the right side, 

 I took and preserved it in gum. The eggs were removed 

 from the surface of the water on a slip of glass gently in- 

 troduced beneath them. These measure between the 

 one-fortieth and one-fiftieth of an inch in length. 



The short line between the two figures indicates the 

 actual length of the body of the Tipuladian Gnat. 



