2Q6 ON AILANTHINE. 



The experience of my friend Dr. Gudward is as follows : 



>Eggs hatched 19th Sept. 



28th " 1st change began. 



5th Octr. 2nd change began. 



12th Octr. 3rd change began. 



21st Octr. 4th change began. 



3rd Not. began cocoon. 



The temperature ranged from 47° to 55°. 



The Cocoon. I have already remarked that after a short period 

 of torpidity when no more food is taken and during which the 

 remains of the undigested food is passed by the worm in abundance, 

 it begins its cocoon by fastening .some threads of silk to the end 

 of the branch or leaf stalk, and, after binding some leaflets 

 together, it spins its cocoon in the hollow thus formed. The 

 colour of the silk is of a yellowish brown colour, very like, indeed, 

 to that of a decayed leaf. In weaving its coco on this worm leaves 

 at its lower extremity, an elastic opening for the exit of the moth. 

 The threads at this opeuing are not cut aeross, but simply turned 

 and laid one over another. The silk of this worm has not as yet 

 been unwound in a continuous thread ; this, doubtless, arises from 

 the substance which glues the threads together requiring some other 

 solvent than the warm water which so readily affects the solution 

 of the gummy secretion of the mulberry silk. This however can- 

 not long remain undiscovered in this country, as a chemical sol- 

 vent for this secretion will doubtless ere long be found.* In China 

 even there is reason to believe that this has been accomplished, 

 as the last examples of ailanthine from that country are stated to 

 leave no doubt of their having been unwound from the cocoon. 

 Even the carded silk of this worm is abundantly used. In China 

 it forms the most durable dresses of the peasantry, —dresses which 

 are often handed down from father to son. In France this "flos- 

 ille " or floss silk is abundantly used for weaving with thread and 

 wool, and in the manufacture of fancy stuffs. At Roubaix, Nismes, 

 and Lyons, it is imported from abroad in large quantities to the 

 extent of 1,290,000 kilogrammes annually. 



Mons. Geoffrey St. Hilaire, President of the Societe d' Acclima- 

 tization of Paris says : — " Here is the report of the weavers at 



*It has been stated by some that the cause of the silk not winding off, 

 results from the slanting opening at the bottom of the cocoon, admitting 

 water, and thus sinking it and breaking the thread. This explanation is 

 not satisfactory and is inconsistent with fact. 



