238 ENTOMOLOGY. 



caterpillar is produced, which is the second stage. 

 It is at first very minute, but in this state it feeds, 

 some kinds on one or two plants, others promiscu- 

 ously on many, continuing to increase in size, and 

 moulting several times the outer skin, until the des- 

 tined period of their dormant state approaches. 



When this arrives, they spin a web more or less 

 strong according to their species, and are converted 

 into the aurelia or chrysalis, named also pupa, from 

 their swaddled appearance, which is the third stage ; 

 and, lastly, they burst forth in due season a perfectly 

 formed winged insect, which is the fourth and last 

 stage. 



In this condition they propagate a future race, and 

 perish themselves ; for the males rarely survive the 

 inclemency of the first winter, and the females of 

 winged insects die after having deposited their eggs.* 



The Ephemera. 



This is the scientific name of the gnat, which as- 

 cends and descends over stagnant pools. 



The Cells of Bees. 



There are only three figures that will enable a car- 

 penter to fill a certain space with cells, without losing 

 any space between them, viz. the square, the equi- 

 lateral triangle, and the figure of six sides. The last 

 is the most convenient and strongest, having some- 

 thing the figure of the arch. A circle would be still 

 stronger, but some room would be lost. The bees 

 build their cells exactly in the six-sided form, and 

 thereby save both space and materials. 



* The larva of certain tipulae and phalenae inhabit the water, 

 but when arrived at their winged state, are readily drowned if 

 immersed in their original element. The larva of a carnivorous 

 beetle moved briskly in a phial of strong alcohol the day after it 

 was put in. 



