92 PRIZE ESSAY: 



I afterwards ascertained that they had penetrated to the depth 

 of more than an inch, and were of a whitish colour, softer and 

 more active than they had previously heen. The fact is thus 

 established, that these apparently torpid larvse, when they fall 

 from the ripe wheat in autumn, or are carelessly swept out from 

 the threshing floor into the barn yard, at once resume their ac- 

 tivity, and bury themselves in the ground. 



" The larvse thus buried in the ground, were allowed to remain 

 undisturbed during winter and spring, the flower-pot being occa- 

 sionally watered. About the end of June they began to reap- 

 pear above the surface, in the winged form ; the little grubs 

 creeping to the surface, and projecting about half their bodies 

 above it, when the skin of the upper part burst and the full grown 

 winged midge came forth and flew off. This completes the round 

 of changes which each generation of these little creatures under- 

 goes, and we have thus actual evidence of each stage of its pro- 

 gress from the egg to the perfect insect." 



157. Dr. Fitch's observations do not agree in one particular 

 with those of Mr. Dawson. The following extract from the 

 paper published in the Rural New Yorker, before referred to, 

 explains Dr. Fitch's views : 



" The insect does not moult or cast off its skin from the time 

 it leaves the egg until it enters its pupa state, nor do I think the 

 larva skin forms a case or envelope within which the pupa lies, 

 but that the skin of the larva gradually changes and becomes 

 the skin of the pupa, as it certainly does in our willow gall-fly 

 (Cecidomyia Salicis. FITCH. ) I infer this from the fact that 

 in those instances in which I have reared these flies from the 

 larvse, the empty pupa skins were the only ones which I found 

 remaining." * 



" Gather a number of the worms from the wheat at the time 

 of harvest and place them in a pill box. They all soon cease 



