196 MAINE AGRICULTURAL EXPERIMENT STATION. 1916. 



PAGE 



PRACTICAL MEASURES 220 



(1) These Flower-flies which are often mistaken for stinging wasps 



or bees are entirely harmless and should not be killed 220 



Several methods of distinguishing them from wasps and bees, 



which they closely resemble, are given 220 



(2) The larvae among aphids on plants should never be destroyed 



but carefully protected 221 



(3) Investigations under way, indicate that certain contact in- 

 secticides can be used to kill the aphids, which will not kill 

 the larvae of Syrphidae, and thus leave these beneficial larvae 



for further usefulness 221 



(4) In late summer many of the Flower-flies are destroyed in the 

 puparia by small Hymenopterous parasites . . .221 



Infested puparia may be recognized and should be destroyed wher- 



evef found 221 



EXPERIMENTS DURING 1915 221 



About twenty species of Flower-flies have been reared in the State 



and studies made of their habits and life stages 222 



PREY ATTACKED BY FLOWER-FLIES 223 



Aphidophagous larvae were found feeding on thirty or forty 



species of aphids and two species of psyllids 223 



DESCRIPTIONS OF IMPORTANT OR INTERESTING 

 MAINE SPECIES. 



Pipiza pisttcoides Williston, an important enemy of the Woolly 



Apple Aphis 224 



Larva 225 



Puparium 226 



Adult 226 



Melanostoma mellinum Linne, reared from among Myzus persicae 



on cruciferous crops 226 



Egg 228 



Larva 229 



Puparium (of peculiar stiuctural interest) 230 



Adult 230 



Sphaerophoria cylindrica Say, is a common and important enemy 



of aphids on fruit trees and other plants 231 



Egg 232 



Larva 232 



Puparium 233 



Adult 233 



Allograpta obliqua Say, a species apparently rare, but occurring in 

 the State, is distinguished from the last two species which it 



closely resembles 234 



Hgg 234 



Larva 234 



