298 DESTRUCTIVE INSECTS. 



stance shows the fallacy of those arguments in which 

 it is stated, that sowing- ten days after the turnip land 

 is ploughed, or fallowing- two years successively will 

 destroy or banish the insect from the crop. 



Cecidomya tritici. We are indebted to Messrs. 

 Gorrie* and Shirreff for almost all that is known of 

 this silent working, and generally unnoticed enemy 

 of the farmer. Entomologists had long ago enrolled 

 this insect in their lists, but they were not aware of 

 the destruction it causes to the wheat crop. This small 

 fly generally makes its appearance along with wheat- 

 ears, i. e. about the middle of June. " They seem at 

 first to frequent the vegetable kingdom indiscrimi- 

 nately, but soon congregate in wheat fields, and 

 remain during day on the lower parts of the plants. 

 About sunset the fly becomes active and continues so 

 till sunrise. Possessing a hair-like ovipositor of con- 

 siderable length, the parts of which slide from each 

 other like the tubes of a telescope, by which the eggs 

 are deposited in clusters, visible to the naked eye on 

 the inside of the chaff, commonly when the ear is 

 escaping from the sheath. The maggots, when 

 ushered into life, are very small, and perfectly 

 translucid; they soon increase in size, and become 

 yellow coloured. They seem to subsist in the first 

 instance on the pollen, and latterly on the matter 

 which would have formed the grain. They possess 

 not the power of moving from one cup to another, 



Of Annat, Perthshire. 



