THE CHIRONOMIDyE. 175 



deposited. These eggs are in the form of long threads of a gelatinous 

 nature, in which the ova are embedded in a row. Fig. 38. They are 

 usually placed at the side of some weed or twig in the water in nature ; 

 in confinement, at the side of the bell-glass or whatever they are con- 

 tained in. The pupa on depositing a large number of eggs generally 

 dies, and here again we observe a difference to Ceddomyta, where the 

 maggots eventually turn to perfect flies. Occasionally the pupae do 

 develop, but during the summer this is only exceptional. When 

 the autumn approaches the flies always hatch, and after copulation 

 deposit fecundated ova in the water and die at once. Grumm 

 notices a curious point in this ; he says that if the ova are taken 

 from an unfecundated fly they develop just the same during the 

 autumn, only development is of longer duration. 



PiipcE of Chironomi. 



In many respects the pup^ of these midges resemble those of 

 gnats. They are naked, no puparium or case of any kind being 

 present. They remain at the bottom of the water until near the 

 time for the emergence of the perfect insect, when by various move- 

 ments they approach the surface. The power of swimming seems 

 to be present in all the aquatic forms. Two things are necessary for 



Fig. 39. — Pupa of Chironotuiis plumosits. 



the extrication of the imago, first, that the thorax, which is always 

 placed upwards, should be slightly above the surface of the water ; 

 and, secondly, that the chrysalis is level with the surface. The 

 imago escapes by the splitting of the Jupper region of the thorax, 

 which has a curious power of repelling water. The insect on coming 

 out of the orifice formed in the thorax, places its legs on the water, 

 and by degrees draws itself completely out of its shell, the case 

 forming a boat, much in the same way as seen in the gnat. On each 

 side of the thorax is a bunch of hairs (five in C. plumosus), which 

 form a star when expanded ; the^ anus is also provided with a fan- 



