160 THE ENTOMOLOGIST. 



the ' Entomologist.' My own record of the time of its 

 existence in the larva state differs from the statement of your 

 correspondent. Six weeks, or a day or two beyond, is its 

 invariable period, at least in the vicinity of London. It is 

 well known that various causes (temperature for instance) 

 will accelerate or retard the growth of a larva ; in this case 

 the locality mentioned appears, to me at least, more favour- 

 able to a rapid development. The " pad" of silk referred to 

 is, I think, only spun by the larva at the different periods of 

 ecdysis, although it may occasionally continue upon it for a 

 short time beyond, until it has consumed the leaves which 

 are immediately around it. Upon the subject of the moth's 

 extrication from [the cocoon many speculations have been 

 advanced, some of the older naturalists attributing the result 

 to friction, others to a solvent fluid, I have no doubt this 

 latter is the agent employed. It has usually been my prac- 

 tice to remove the pupa from the cocoon previous to 

 emergence. Of course, though the solvent is not then 

 needed, it would still be ejected by the moth ; and I have, in 

 fact, often seen this liquid on the moth's first appearance 

 from the puparium. It appeared certainly to flow from the 

 head, of sufficient quantity to form a bead, of a lightish pink 

 colour, which rested just above the first pair of legs. I be- 

 lieve it to be of a powerfully acid nature, for, having on one 

 occasion got a little of it under a finger-nail, I found a slight 

 irritation produced by it. On one occasion, when I had 

 reared a number of these larvae in a common habitation, 

 some of them made their cocoons in clusters. When ex- 

 amining them I invariably found that those individuals upon 

 whom several other cocoons had been superimposed were 

 dead, perhaps from an exclusion of air. — JoJm R. S. Clifford ; 

 21, Robert Terrace, Chelsea, December 9, 1864. 



100. Scarciijj of Bombyx nevslria. — This insect has been 

 exceedingly scarce in the west and south of the vicinity of 

 London for some years. Last year I only picked up a soli- 

 tary larva. I should be glad to hear whether, in other 

 localities, it has appeared as usual. Far different was it with 

 that connnon Tinea, Yponomeuta Padella. In many places, 

 last summer, near my residence, countless numbers of these 

 larvae appeared, extending their ravages from the hawthorn, 

 their favourite food, to all other shrubs growing near, care- 



