SYRPHIDAE OF MAINE. I97 



PAGE 



Puparium 235 



Adult 236 



The American Syrphus-fly, Syrphus americanus Wiedemann, a 

 very general feeder, is one of the most valuable species in the 



State . . .236 



Egg ' 237 



Larva .- 237 



Puparium 238 



Adult 239 



Syrphus torvus Osten Sacken also occurs in great numbers among 



certain species of aphids 240 



Larva . . 240 



Puparium . 241 



Adult 241 



Syrphus nitens Zetterstedt, a European species not heretofore 

 recorded from North America, is aphidophagous and of par- 

 ticular biological interest, because of structural peculiarities 242 



Larva 242 



Puparium 244 



Adult 244 



Didea fasciala Macquart var. fuscipes Loew occurs feeding among 



the Willow-grove Plant-louse 246 



Egg ■ 246 



Larva 247 



Puparium. ... :.'.'. 248 



Adult 248 



7 ropidia quadrata Say whose larval habits are here recorded for 



the first time, was found breeding in human excrement 248 



Egg - 249 



Larva 250 



Puparium. . 251 



Adult 252 



The very common Syritta pipiens Linne was also reared from 



human excrement and from guinea-pig manure 253 



Egg • 253 



Larva 254 



Puparium 254 



Adult }. 255 



ARTIFICIAL KEYS TO THE LARVAE AND PUPAE OF 



SYRPHIDAE. 256 



GLOSSARY OF NEW OR UNUSUAL TERMS 258 



BIBLIOGRAPHY 261 



FIGURES 264 



