200 MAINE AGRICULTURAL EXPERIMENT STATION. I916. 



In spite of their lack of popular recognition, I have become 

 convinced during several years' study of this group, that, in 

 the sections observed, the Flower-flies are a more important 

 enemy of aphids than are the Lady-bird Beetles, and that 

 probably they are the most important of the natural enemies 

 of aphids. I have been gratified to find this opinion confirmed 

 by Dr. Edith M. Patch after many years' extensive observa- 

 tions of the aphids of Maine. 



The present bulletin deals with only one of the groups of 

 insect enemies of aphids, — the Syrphidae. Its aim has been 

 to elucidate the life-economy of these little-understood Flower- 

 flies, so that the agriculturist may come to look upon them as 

 his friends and give them his well deserved protection. And 

 that as a basis for fostering and increasing their numbers we 

 may have an intimate knowledge of their structure, habits and 

 transformations. And since the larval habits are very diverse, 

 not all being enemies of aphids and a few quite injurious, it 

 has been deemed important to study all the species of whatever 

 larval habit so that we may learn to distinguish the injurious 

 and the beneficial ones. 



What Flower-Flies Are. 



The family Syrphidae is one of a number of families com- 

 prising the great order of insects known as the Diptera, or 

 two-winged flies, (characterized especially by the possession 

 of 'a pair of knobbed threads, halter es, on the thorax in lieu 

 of the second pair of wings) and to the sub-order Cyclorrhapha, 

 section Aschiza. 



They are medium to large flies, sometimes uniformly black 

 but usually very brightly-colored ; being characteristically 

 striped, spotted or banded with bright yellow on a blue, black 

 or metallic ground-color. The yellow occurs especially com- 

 monly as transverse bands or fasciae on the abdomen, but also 

 on thorax and head. This black and yellow coloring gives them 

 a general, and often a particular and very striking resemblance 

 to wasps and hornets for which they are commonly mistaken. 

 Other species are covered with long black and yellow hairs 

 and resemble bumblebees. This resemblance to Hymenoptera 

 is further heightened by their habit of visiting flowers for 

 nectar and pollen. 



