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the silk glands, becomes perceptibly re- which escapes and wets the fore end of 

 duced in size. It has been estimated that the cocoon, causing the resinous material 

 the larva, in attaching the continuous binding together the fibres to become 

 thread of its cocoon, makes two hundred soft. Even cocoons sealed up in shellac 

 and fifty-four thousand back and forward and starch have been dissolved by this 

 movements. The cocoons are very fluid, and thus the moths have been able 

 strong and dense, of a dirty white color to escape. When the cocoon has become 

 and generally coated with a white pow- sufficiently soft, the moth pushes its way 

 der, the female being the larger. between the fibres, but in doing so often 

 There is but a single brood in the breaks some of the threads, thus making 

 north, while in the south there are two. the silk of such cocoons useless for corn- 

 In order to see if the pupa needed air, mercial purposes. The moth at the time 

 Mr. Trovelot sealed up some cocoons of emergence, with its folded and crum- 

 over winter in shellac, but the moths pled wings, is quite a forlong-looking ob- 

 emerged in due time after being in an air- ject. These wilted wings soon begin to 

 tight space for nine months. He also de- fill up with fluids from the body, which 

 layed the emergence of the moth till is very large at this time. In some cases, 

 twenty-one months after entering the the fluid is driven into the wings with so 

 cocoon by placing it upon ice. much force that they swell up, and if such 

 The silk in the spinning glands before a wing is punctured, thus allowing some 

 it is spun is a clear, transparent fluid, of the fluid to escape, the mature wing 

 These glands seem to be of excessive size will be of a smaller size than one from 

 when compared with that of the larva, which no fluid has been lost. It must be 

 since, when fully expanded, they reach remembered that it is possible to inflate a 

 the great length of twenty-five inches, or butterfly or moth's wing, because the 

 about eight times the length of the full- wings of insects are not composed of a 

 grown larva. These glands are paired, single layer, but are sacs of two layers 

 one being found on each side of the body, which are closely applied. It is thus pos- 

 are considerably folded and taper at each sible to split the wing into upper and 

 end. The ducts leading from the anterior lower halves, but this can only be done at 

 end of the glands unite to form a single the time of emergence, when these two 

 duct which opens below the mouth. The layers are not so firmly cemented togeth- 

 thread is double, being really composed er as they are in a few hours after emer- 

 of two different fibres, one from each gence. 



gland, as may be shown by separating The enemies of Polyphemus are. nu- 

 them. The silk in these glands is pre- merous. Birds prey upon the larvae, in 

 pared and sold as silk "gut" to anglers, addition to numerous parasitic insects 

 On account of its transparency when in which are very similar to those which de- 

 water, it becomes invisible and thus aids stroy Cecropia. The cocoon itself is not 

 in deluding the wary fish, who does not a complete protection because rats and 

 see any connection between the line and squirrels plunder them. We thus see 

 the baited hook. The "gut" is prepared that the life of even an insect is full of 

 as follows : Larvae which are ready to dangers, and that it is really a wonder 

 spin their cocoons are cut open and that so many are able to become mature 

 placed in strong vinegar for eighteen and reproduce. 



hours ; the glands are then taken out, The silk-worm moths are excellent il- 



stretched and dried in the shade. lustrations of what is called complete 



Six or eight days after beginning the metamorphosis in insects. An insect like 



cocoon, the larval skin is moulted and the the grasshopper, w r hen it hatches from 



real chrysalic or pupal stage begins. This the egg, is very much like the adult in- 



stage normally lasts till the following sect in its general form and appearance ; 



spring or summer. A few days before the most evident difference being the lack 



the time of emergence a pair of glands of wings. An insect which shows such 



which open into the mouth become very slight changes in its growth to maturity 



active and secrete an acidulated fluid is said to have an incomplete metamor- 



