THE MICROSCOPE AND INSECT LIFE 



pointed at one end and blunt at the other. Every 

 egg is arranged with its blunt end downwards for, 

 from that end, the larvae gnats make their way into 

 the water. A larva, it may be explained, is the stage 

 in insect development which follows the egg; the 

 next stage is known as the pupa. When the eggs 

 are first laid they are white but, before they hatch, 

 they become darker and darker, till they are almost 

 black. The larvae which hatch from the eggs we 

 must examine under our microscope and also in 

 the water — they may easily be kept in a small jar 

 of pond water. If we study their habits carefully, 

 we shall observe that they float almost at right 

 angles to the surface of the water and that, while 

 doing so, the tip of a little peg-like outgrowth on 

 the tail end of their bodies is thrust out of the water. 

 The little peg is the breathing organ of the gnat 

 larva and the flaps which open and close at its tip 

 are worth examination. In a few days, the denizens 

 of our pond water will change their appearance and 

 become comma shaped. On their heads we shall 

 see a pair of curious horns, which project out of the 

 water as the creatures, which have now become 

 pupae, float at the surface. The horns are breath- 

 ing organs. As we examine these pupae, day by day, 

 we shall see the various parts of the complete gnat 

 as they develop within the body of the comma. 

 Finally, under the microscope, we can trace all the 

 parts of the gnat. Darker and darker the little 

 creatures become, as development proceeds; at the 

 same time they become less active and less comma 



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