Sentence:  black swallowtail&#x5D; does not—as a true insect does—change from worm to grub, and from grub to his mature form, but simply “shuffles off his <WSD>mortal coil</WSD>,”—skin, hairs, and leggings all complete, now and then, .... He then leaves his shuffled-off “<WSD>mortal coil</WSD>” hanging upon a fragment of dirty cobweb, as before described. 
Meaning of the word marked with <WSD> tags:  The physical body of man (containing the spirit inside).