82 INSECT TRANSFORMATIONS. 



with the greatest regularity, after the manner of a 

 candle-shade, and the down tiled upon it all round. 

 Another of our prisoners, though precisely in the same 

 circumstances as to space, instead of forming- a wheel, 

 piled up her eggs in form of a circular mound ; but as 

 the number of her esgs was not a sixth part of those 

 of the other, (probably from her having deposited part 

 before we caught her,) this may have induced her to 

 vary the shape of the group. Like the others, how- 

 ever, the regular slope and tiling of the down was 

 carefully preserved* We have now (April, 1S30) a 

 numerous brood of caterpillars from these very eggs. 



The eggs, \yhich are thus deposited with so much 

 care, are destined to abide all the pitiless pelting of 

 the storms of winter ; for, although they are laid in 

 August, they are not hatched till the elm comes into 

 leaf in the following spring. The covering of down, 

 accordingly, from the manner in which it is tiled and 

 brushed smooth by the mother moth, not only protects 

 them from wet, but from severe cold, being one of the 

 best non-conductors of heat. The experiments of 

 modern chemical philosophers have proved beyond a 

 doubt, that the warmest material for clothing is not 

 what imparts most heat to the body, but what best 

 prevents tlie escape of the heat generated there. The 

 feeling of cold, therefore, does not, as might be suj)- 

 posed, arise from anything positively cold, but solely 

 from a deficiency of heat. On putting the hand, for 

 example, on a piece of ice, the feeling of cold does 

 not arise from cold given out by the ice to the hand, 

 but fiom the heat which the ice takes from the hand, 

 which heat can be actually traced in the water formed 

 by the melting of the ice. But when the hand is laid 

 upon wool, feathers, or down, these do not feel cold, 

 because they do not carry off the heat of the skin so 

 rapidly as the ice. 



* J. R. 



