216 ENTOMOLOGY. 



their organism, which is caused by a less substantial nourishment, and pro- 

 pagated from generation to generation. Also that the disease is cured or a 

 favourable amendment produced, by sprinkling the mulberry leaves upon 

 which they feed with vinegar, pure or diluted; with sulphuric acid, diluted with 

 water; or powdering with flour of sulphur, or fumigating with sulphurous acid. 



On the contrary the disease called Muscardine is cured or prevented by 

 sprinkling the mulberry leaves with liquid alkalies, which will neutralize the 

 acidity of the blood produced by leaves too rich in nutritive matter, or 

 other unknown causes. 



My reason for believing that the acid disease of Silkworms is produced 

 by leaves too rich in nutritive matter, is that the disease appears princi- 

 pally when they are thriving best — when the trees have no disease — and it 

 appears on the finest and most vigorous worms. The disease appears most 

 frequently at the moment when the worms are best developed, when their 

 aspect is most promising, and when they devour with avidity the excellent 

 leaves procured for them from the best-cultivated trees. 



On the contrary the alkaline nature of the liquids of the worms is mani- 

 fested always when the vital force is weak, produced by an insufficient 

 nourishment; also when the leaves are diseased, when they are given to the 

 Silkworm too old or too young, the want of proper ventilation, a deficient 

 respiration caused by obstructed stigmata — these are the causes which 

 combine to produce excess of alkaline matter in the blood of Silkworms, 

 and all those which die of this cause, arrive at a condition of putrid 

 decomposition. 



This feebleness in the vital functions of Silkworms suffering from alkaline 

 disease is very evident in the worms themselves, and is well known to 

 those by whom they are reared; also the Silkworm is developed slowly, 

 and drags on its existence in a languishing manner; its moult is painful, 

 and often prolonged over several days, and they spin up at different periods. 



It is consoling to believe that this epidemic, which is not contagious, has 

 begun to enter into its period of decline; the Gattine does not now gener- 

 ally attack worms until a later period than in preceding years, and does 

 not shew itself seriously till after the fourth moult. A great number now 

 recover, while in preceding years all perished." 



Nomenclature.-— With reference to Mr. Bree's remarks on the British 

 Museum Lists, in the last Number of the "Naturalist," I have referred to 

 those I have by me and cannot see a single B. M. attached to any of the 

 names of species, as stated by Mr. Bree. So again the list of Diptera gives 

 only the names of those in the British Museum collection, and does not, as 

 he says, on the title-page, in that instance at all events, even profess to give 

 a complete list either of the whole order or of any of the families in it. The 

 same remark applies to the "List of the specimens of Lepidopterous insects in 

 the collection of the British Museum," as thus stated at least on the title-page 

 and the several other lists. It is only on looking into the prefaces that one 

 sees which do give more than they profess on their title-pages, and which 



