INSECTS : THEIE MOtTTHS. 181 



You may also see, on each cheek, close to the base 

 of the mandible, a little pit, out of -which rises a short 

 columnar organ tipped with two bristles ; these columns 

 are the incipient antennce. Outside them you may dis- 

 cern on each cheek, a series of six globes of glass (so 

 they appear) set in the substance of the skin, — five form- 

 ing a semicii'cle, and one in the centre ; these are " the 

 windows at which the [silkworm's] soul looks through," 

 — provided he has any soul — in prosaic parlance, his 

 eyes. 



Now, having thus introduced the several members 

 of our useful friend's ph^^siognomy to you, let me call 

 your attention to a fleshy wart just beneath the lower 

 lip, and midway between the bases of the two fore legs. 

 This wart terminates in a horny point not unlike a bird's 

 beak, which is perforated, and from the tip of which the 

 glistening yellow filament of silk is ever drawn out, as 

 the caterpillar throws his head from side to side. This 

 pointed wart is the spinning organ ; and the thread of 

 silk is, as it issues from the orifice, a fiuid gum, which 

 hardens immediately on its exposure to the air. The 

 silk-gum is secreted by the caterpillar in two long blind 

 tubes, which lie twisted and coiled in the interior of the 

 body, occupying nearly the whole space, except that 

 which is taken up by the great digestive canal. These 

 become very slender as they approach the head, and at 

 length terminate in a dilated reservoir, which opens by 

 the little pointed wart which you have just seen. 



Many caterpillars are able to suspend themselves at 

 pleasure by means of the thread which they are spin- 

 ning, lengthening it and " stopping it oif," at will. This 

 latter operation they perform (though they cannot recal 

 the thread when once it has issued) by means of an an- 



