Cocoons, Nests and Eggs 



therefrom, which projects nearly an inch above the surface 

 of the water. 



The completed structure, as it floats on the water, 

 resembles a chemist's retort, with a narrow neck projecting 

 into the air. In this curious little ark the larvae remain 

 but a short time after they are hatched, before eating their 

 way out to the surrounding water. 



Familiar as is the common cockroach, there are many 

 people who have never seen its remarkable red-brown egg- 

 case, which resembles nothing so much as a miniature 

 snap-purse. Each case contains sixteen eggs, deposited 

 in two rows, side by side, in such a manner that the ends 

 of the eggs, from which the young cockroaches will hatch, 

 all point towards the opening of the case. The horny, 

 purse-like structure is kept closed at its upper edge by 

 its natural elasticity, so that when the young roaches 

 hatch all they need do is to push their way out of their 

 temporary hiding-place. The mother roach displays the 

 greatest concern in seeking a suitable shelter for her egg- 

 case. Case and eggs are formed within her body, and 

 she will sometimes walk about for days with the egg-case 

 partly protruding from her body, till she finds a spot 

 where she thinks no harm can come to her precious 

 burden, and there she leaves it. 



Many other insects protect their eggs by means of 

 cases ; certain locusts, for example, deposit their clusters 

 of eggs in holes in the ground, and cover them with a 

 sticky substance which sets moderately hard and forms 

 a case around them. The gadflies deposit their eggs in 

 curious masses, and so do the mantids. A mantis egg- 

 case is worth a moment's consideration. In its completed 

 form it is hard and horny, but at the time of its formation 

 it is soft and spongy. The egg-cases vary in size 

 according to the species of mantis, but many of them are 

 more than an inch and a half long. They are usually 

 yellowish-green in colour, and the eggs within are 

 arranged in regular rows. When the eggs are being 



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