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A BRIEF STUDY OF A FEW CECIDOMYIIDAE 

 By Dr. J. C. Chapais, St. Denis (en-bas). 



Though I am not an entomologist by vocation, it happens, now and then, that 

 I make an excursion in the field of entomology to find out those insects that 

 are either noxious or useful in agriculture so as to establish the amount of their 

 noxiousness or of their usefulness and to learn how to destroy or protect them. 



This is the reason why I wish, to-day, to make this brief study concerning a 

 few insects of two or three genera of the nematocerous Diptera (insects with fla- 

 mentous antennae) or small two-winged flies, typical of the family Cecidomyiidae. 

 The family comprises a vast number of minute slendered-bodied midges, which 

 are of special interest on account of their mode of life, the peculiar structure ex- 

 hibited in the larvae and the economic importance attached to several species. In 

 most cases, the female lays her eggs in the stems, leaves or buds of various plants^ 

 producing gall-like excrescences of various forms inhabited by the larvae. 



The iiessian fly. Mayetlola destructor (Say). Healthy wheat stock at left and infested stock at right; 



a— larva; c— puparium or "flaxseed"; d~pui)a exposed; e^adult female laying eggs; f— female; 



g— male; h— puparia or '"flaxseed" in natural position between leaves and stalk; i— parasite 



(Merisirs destructor). (Slightly enlarged, excepting e. whis is smallar than natural). 



(Aiter Riley, Burgess and Forbes) 



Some species, however, do not produce galls, and among them are the 

 Hessian fly, Cecidomyia destructor or Mayctiola destructor, Say (Cccidomie des- 

 tructrice) ; the Dasyneura Icgnminicola Lint, Clover flower-midge. Clover seed- 

 midge {le moucheron du trcfle) and the Dasyneura rhodophaga Coq, Rose-midge 

 (Moucheron de la rose). These last three mentioned insects, and another one 

 which produces galls on the fruit of the Choke-Cherry tree {Cerasus Virginiana) 

 and called Cecidomyia or Coutarinia Virginiajia will be the subject of the few 

 notes I intend to communicate to you in. the present study. 



I do not pretend to impart new knowledge concerning the Cecidomyiidae in 

 the following notes. All I mean to do is to extract from a few bulletins, written 

 in English, the substance of what they contain about the four insects above men- 

 tioned and to communicate it in the French version of our report to my French 



