88 FOURTH ANNUAL REPORT OP ^ 



though whether Hymenopterous or Dipterous I have not been able to lean:!' 

 with assurance. 



Several diseases of a fungoid or epizootic nature and several maladies 

 which have not been sufficiently characterized are, however, well known to 

 afflict this worm. One of these diseases called muscardine, has been more or 

 less destructive for many years in Europe. It is of precisely the same nature 

 as the fungus {Einpusa muscce) which so frequently kills the common House- 

 fly and sheds a halo of sporules, readily seen uj^on the windoAV-pane, around 

 its victim. 



A worm about to die of this disease, becomes languid and the doi*sal juil- 

 eations become insensible. It suddenly dies and in a few hours becomes >.tiff, 

 rio'id and discolored; and finally, in about a day, a white powder or efflor- 

 escence manifests itself, and soon entirely covers the body, developing must 

 rapidly in a warm humid atmosphere. No outwai'd signs indicate the tirst 

 stages of the disease, and though it attacks worms of all ages, it is^by far the 

 most fatal during the fifth or last age or stage. 



This disease was proved by Bassi to be due to the development of a fun- 

 gus (Botrytis Bassiand) in the body of the worm. It is certainly infectious j 

 the spores when they come in contact with the worm, germinating and send- 

 ing forth filaments which penetrate the skin and, upon reaching the inter- 

 nal parts, give off minute floating corpuscles, which eventually spore in the 

 efflorescent manner described. Yet most silkworm raisers, including such 

 good authorities as E. F. Guerin-Meneville and Eug. Robert,* who first implic- 

 itly believed in the fungus origin of this disease; now consider that the Botry- 

 tis is only the ultimate symptom — the termination of it. At the same time 

 they freely admit that the disease may be contracted by the spores of the 

 botrytis coming in contact with worms predisposed, by unfavorable condi- 

 tions, to their influence. Such a view imjjlies the contradictory belief that 

 the disease either may or may not be jn'oduced by the fungus; and those 

 who consider that the fungus is the sole cause have certainly the advantage 

 of consistenc}". 



Whichever view be held, it appears very clear that no remedies are 

 known ; but that care ii\ procuring good eggs, care in rearing the worms, 

 good leaves, pure, even-temperatured atmosphere, and cleanliness are checks 

 to the disease. The drawers and other objects with which diseased worms 

 have come in contact should also be purified by fumigations of sulphuric 

 acid, which will destroy all fungus spores. 



This muscardine, or a disease which has not yet been distinguished from 

 it, has also made its appearance in some of the Eastern States among silk- 

 worms, both imported and wild; and in the fall of 1870 it was so common 

 around St. Louis, that I found hundreds of caterpillars stiffly fastened to 

 their food plants and covered with the white efflorescence. It was especially 

 noticeable among the " AVooly-bears," or hairy caterpillars of our difterent 

 Tiger-moths (Arctians); and as the efflorescence is not very apparent at the 

 base of the long dense hairs, such diseased caterpillars look quite life-like. 



♦See their Guide ;l I'eleveur tk- vers a soie. 



