200 LEPIDOPTERA. 



are kept in cold, dark places, the development is 

 retarded, and when kept in a warm schoolroom, it is 



quickened, so that the 

 pupae will often trans- 

 form as early as the sec- 

 ond week in iVpril. When 

 the pupa is ready to 

 come out of the cocoon, 

 it secretes a liquid con- 

 Fig. 152. taining bombycic acid, 

 which dissolves the gum 

 uniting the silken threads : it then escapes without 

 breaking a fibre. On the right of Fig. 151 is the open- 

 ing where the moth came out, and on the edges the 

 silken fibres are distinctly seen. The silk is valued 

 highly for its strength and glossy lustre. After the 

 moth is free, let the pupils examine the empty co- 

 coon. It is moist inside, and the cast-off pupa-skin 

 is found within, attached to the end opposite the 

 opening. 



TINEID/E. 



The clothes-moth, Tinea pellionella, Linn. (Fig. 

 153, i) is a small buff-colored insect which is some- 

 times seen flying about our rooms in April and May, 

 but seldom in the vicinity of bright lights. When the 

 wings are spread, these moths do not measure more 

 than half an inch in breadth, and are, therefore, much 

 smaller than the " millers " that fly around lights, and 

 are erroneously supposed, by some, to eat woollen 

 garments. The head of Tinea looks like a small 

 cushion of hairs ; the eyes are small, but the antennae 



