BULLETIN 253 



SYRPHIDAE* OF MAINE.** 



C. L. METCALF.f 



SUMMARY. 



PAGE 



INTRODUCTION .....' 198 



Man's greatest allies in controlling destructive insects are other 

 species of insects having the predaceous and parasitic habits; 

 without the help of which he would doubtless be unable to 

 protect his crops against the multitudes of destructive' pests ... 19S 



It is therefore deemed important to study our native beneficial 



insects in detail as a basis for increasing their usefulness 198 



One of the most important groups of natural enemies of the Aphi- 

 didae or plant-lice is the family of Flowei -flies or Syrphidae 

 which are not well-known and are much misunderstood 199 



This bulletin deals with the structure and habits especially of the 



immature stages, and of both beneficial and injurious species 200 



WHAT FLOWER-FLIES ARE 200 



The two-winged flies of this family are easily recognized by the 



"false vein" on their wings. (Figs. 31-64, 35-1) 201 



Other characteristics 201 



HOW FLOWER-FLIES LIVE 201 



The Flower-fly has a complete metamorphosis including four dis- 

 tinct life stages . . . . , 201 



Egg: 



The eggs are deposited by the flies in a great variety of situations 201 



They have a somewhat characteristic appearance ^02 



* Pronounced Surf'-i-dee. 



**Papers from the Maine Agricultural Experiment Station : Ento- 

 mology 87. 



tMember of the Station summer staff. 



