THE STATE ENTOMOLOGIST. 91 



abroad jirovecl to be infected witb the disease j and though upon recogniz- 

 ing it he immediately destroyed the larva^, and at that time his Polyphe- 

 mus eggs were not yet hatched — the precaution was of no avail, as the 

 infection was about the house, and the native worms all eventually died 

 of it. Speaking of this fearful disease among them, Mr. Trouvelot writes 

 me : " A few daj^s after the third moultings the worms begun to manifest 

 symptoms of the deadly disease, and two or three days after, of a million, 

 I had but a single one left, and this one even died in the pupa state. The 

 following year, I thought I could begin anew, but I found that the epidemic 

 had sjDread among the wild ones and all those I found were attacked with 

 it, even to a distance of seven miles from my place. But the disease did not 

 spread further as I had feared, and the third year the wild individuals were 

 as robust as usual, but the disease, or at least the seed of it was infesting 

 my buildings, and as soon as the healthy wild PolyiJhemus would approach 

 them the}' became sick and died." Of late the disease has also been intro- 

 duced by means of Italian eggs, into China and Japan ; and while it is on 

 the decrease in Europe, it bids fair to run a fearful course, unless prevented, 

 in these the native countries of the silkworm: 



Fehrine, as we have already seen, difters from muscardine in being her- 

 editary as well as infectious. It will not suffice, therefore, simply to take 

 the precautionary measure of purification and cleanliness advocated for the 

 latter; we must also take care that our eggs are sound, by microscopic ex- 

 amination of the moths. This may be done after the eggs are laidj and if 

 the corpuscles are found in the mother, her eggs should be discarded. 



Silkworms are subject to other diseases but none of them have ever ac- 

 quired the importance of those described. What is called gattine by older 

 authors is but a mild phase of pebrine. The worms are apt to be purged by 

 unwholesome leaves; they get sickly by too great heat; they become yel- 

 low, limp and die of a malady called grasserie or jaundice, which is almost 

 sure to appear in large broods, or as the French more appropriately say, 

 educatio7is, and which I have most frequently noticed in those reared in this 

 country. When the worms die from being unable to moult they are called 

 lusettes ; and such worms are most abundant in the third age. All these dif- 

 ferent ailments and others, not mentioned, have received names; some local, 

 others more general; but they none of them warrant further notice here, 

 as they are not likely to become very troublesome if the proper attention 

 and care be given to the worms. 



BEST VARIETIES, OR RACES. 



Since the diseases just mentioned have been so prevalent in Europe, 

 among the French and Italian races, the Japanese annuals have been the 

 most esteemed. The eggs are bought at Yokahoma in September, and ship- 

 ped during the winter. There are two principal varieties in use; the one 

 producing white, and the other greenish cocoons, and known respectively 

 as the White Japanese and the Green Japanese annuals. These cocoons are 

 by no means large, but the pods are solid and firm, and yield an abundance 



