340 



already affected, by the introduction beneath the skin of the former 

 of some particles of the diseased portion of the latter, and it then 

 spreads in the fatty mass beneath the skin, occasioning the destruction 

 of this tissue, which is very important as a reservoir of nourishment 

 to the animal when about to pass into a state of complete inactivity. 

 The plant spreads by the extension of its own structure, and also by 

 the production of minute germs, which are taken up by the circulat- 

 ing blood and carried to distant parts of the body. The disease inva- 

 riably occasions the death of the silkworm, but it does not show itself 

 externally until afterwards, when it rapidly shoots forth from beneath 

 the skin. The caterpillar, chrysalis and moth are all susceptible of 

 having the disease communicated to them by the kind of inoculation 

 just described, but it is only the first which usually receive it sponta- 

 neously. The importance of this disease to the breeders of silkworms 

 led, as soon as its true nature was understood, to careful inquiry into 

 the circumstances which favour the production of the fungus, and 

 it has been shown that if bodies of caterpillars which (from various 

 causes) have died during breeding, be thrown together in heaps, and 

 exposed to the influence of a warm and moist atmosphere for a few 

 days (as has been very commonly the case), this fungus almost invari- 

 ably appears upon them, just as other kinds of mould appear on other 

 decaying substances, and that it is then propagated to the living worms 

 by the diffusion of its germs through the atmosphere. The knowledge 

 of this fact, and the precautions taken in consequence, have greatly 

 diminished the mortality. 



I send you the above extract from the ' Popular Cyclopaedia of Na- 

 tural Science,' which I think may be interesting as a variety for ' The 

 Entomologist,' and may furnish some useful remarks to the breeders 

 of moths in this country. — John Chant ; 3, Critchell Place, New 

 North Road, Maij 10, 1842. 



183. Economy of Papilio Machaon. In my notice of the capture 

 of Papilio Machaon (Entomol. 307), I should have mentioned Haver- 

 hill as the place of capture ; on enquiry I found it has several times 

 been taken in that place, but never heard of its occurrence at Laven- 

 ham, nor do I expect to meet with it, except in my own room. The 

 following account of the habits of this splendid species in confine- 

 ment, may be interesting to some of the readers of ' The Entomolo- 

 gist.' Having, in the spring of 1840, obtained a number of chrysali- 

 des from Barwell-sedge fen, near Newmarket, Cambridgeshire, a male 

 and female emerged from them on the morning of the 27th of May, 

 and were left near each other on the window-blind to expand and dry 



