184 EVENINGS AT THE MICROSCOPE 



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

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

 nar organ tipped with two bristles; these columns are the 

 incipient antennae. Outside them you may discern on each 

 cheek a series of six globes of glass (so they appear) set in 

 the substance of the skin five forming a semicircle, 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 physiognomy 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 yel- 

 low 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 fluid 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 spinning, 

 lengthening it and 41 stopping it off" at will. This latter 

 operation they perform (though they cannot recall the 

 thread when once it has issued) by means of an angular 



