FIELD BOOK OF INSECTS. 



M ICRO-LEPIDOPTERA 



Under the above term, "Micros" for short, are roughly 

 grouped a number of families of moths. Not only is the 

 division not very satisfactory from a scientific standpoint, 

 but, practically, many Macros are smaller than some 

 Micros. The term super-family Tineoidea is sometimes 

 used. The families of moths which follow are Micros. 



PSYCHID^E 



Plate LIX shows a bag such as is fre- 



Thyridopteryx ^ quent i y no ticed on many sorts of trees, 

 epnemeraerormis . 



deciduous and coniferous. It is made of 



silk in which are fastened leaves or bits of stick. If we 

 examine such bags during the winter, we will find many of 

 them to be empty but others will be found full of soft 

 yellow eggs. Riley, one of our pioneer economic entomo- 

 logists, wrote as follows: "Those w y hich do not contain 

 eggs are the male bags and his empty chrysalis skin is 

 generally found protruding from the lower end. About the 

 middle of next May these eggs will hatch into active little 

 worms, which from the first moment of their lives, com- 

 mence to form for themselves little bags. They crawl 

 on to a tender leaf, and, attached to their anterior feet 

 with their tails hoisted in the air, they spin around them- 

 selves a ring of silk, to which they soon fasten bits of leaf. 

 They continue adding to the lower edge of the ring, pushing 

 it up as it increases in width, till it reaches the tail and 

 forms a soft of a cone. As the worms grow, they continue 

 to increase their bags from the bottom, until the latter 

 become so large and heavy that the worms let them hang 

 instead of holding them upright, as they did while they 

 were young. This full grown condition is not attained, 

 however, without critical periods. At four different 

 times during their growth these worms close up the mouths 

 of their bags and retire for two days to cast their skins or 

 moult, as is the nature of their kind, and they push their 

 old skins through a passage which is always left open at the 

 extremity of the bag, and which also allows the passage of 

 excrement. During their growth they are very slow travel- 



198 



