Leaders. 89 



ly due to the silk secreted within the worm, and the 

 strength of that silk being universally admitted, its great 

 superiority to the B. mori for our purpose seems to be 

 beyond question. In " On Insects Injurious to Vegeta- 

 tion," by F. W. Harris (Orange Judd Publishing Co., 

 New York, 1863), he says, "as a worm for quantity and 

 durability of silk the Cecropia has so far no equal." 



The worm is apple-green in color, darker below and 

 lighter on the back. Its skin is smooth, except for six 

 longitudinal ranks of fleshy tubercles, two on each side 

 and two on the back. Those on the sides are smaller, 

 cylindrical, and blue in color. On the back the tubercles 

 are larger and yellow, except those on the three segments 

 nearest the head. The latter are larger still, red in color, 

 with small black spots, and shaped like a cabbage head 

 that is, as though fleshy excrescences, about the size 

 and shape of a No. 1 shot, were joined to the body by a 

 fleshy neck. A single tubercle similar in size and form, 

 and yellow in color, is attached to the middle of the 

 back near the tail. It is the only tubercle on the median 

 line of the back. 



The foregoing, it is hoped, will answer for purposes of 

 identification, but those desiring further information can 

 find colored illustrations of both worm and moth (as 

 well as of those hereinafter mentioned, with one excep- 

 tion) in vol. xxxii. of the Naturalises Library (Henry 

 G. Bohn, publisher, York Street, Covent Garden, London). 

 The references will be found on page 132, and the pages 

 following. The Cecropian worm is therein called the 

 " Hyalophora cecropia." A description can also be found 

 in " On Insects Injurious to Vegetation," heretofore al- 

 luded to, and in " The Lepidoptera of North America " 

 (Smithsonian Institution, 1862). 



