6 



It will be seen from this resume of the known larval habits that the 

 habits of the sj)ecies which we are about to treat are quite abnormal 

 in its family so far as known. Moreover, in its tribe, Syrphini, it is 

 still more anomalous for the reason that the only two genera of this 

 tribe of which the larval habits seem to be known, viz, Syrphus and 

 Sj)1ia'}pphoria, are carnivorous, feeding upon Plant-lice. 



Mesograpta polita^ then, as a plant-feeding species is worthy of record 

 as of more or less abnormal habit, as well as on account of its possible 

 effect ui)on the productive qualities of corn. 



In August, 1885, Mr. E. C. Taggart, of Griggstown, Somerset County, 

 N. J., sent to the Department some pieces of fodder corn taken from 

 a field on his place, and which were covered with small yellowish 

 maggots. His corn had not appeared to suffer from their presence 

 and he was at a loss to know to what to attribute their presence. A 

 microscopic examination of the living larvfe showed at once that the 

 alimentary canal of each was full of partly-crushed i^ollen grains, and 

 upon placing the fresh male blossoms of corn in the breeding jar the 

 larvfB clustered upon them and were observed feeding upon the pollen 

 grains. 



Subsequent correspondence with Mr. Taggart showed that the mag- 

 gots were noticed during that season for the first time, and when first 

 observed (the third week in August) appeared to be confined to a single 

 patch of fodder corn, occurring so abundantly as to cover the leaves 

 and congregating most in the axils, where the upper leaves join the 

 stalk. This patch of corn was cut August 22, and thirteen days later 

 when it was partially cured, the worms were observed still living and 

 increased somewhat in size. A patch of fodder corn, distant about 

 one hundred rods from that on which they were first observed, was 

 planted later, and did not blossom until the first week in September. 

 The worms were then found to appear on this patch also, and again the 

 " stalks became literally covered by them." Strange to say they oc- 

 curred only in these two patches on Mr. Taggart's place ; other fields 

 examined by him were entirely free from the worms. 



From specimens received from Mr. Taggart August 31 the adult flies 

 were bred September 7 to 15, the larvte having become coarctate a day 

 or so after arrival. These flies were determined by Dr. Williston as 

 Say's Mesograpta polita, a species which has a wide range throughout 

 the United States east of the Mississippi, and which is also found in 

 Cuba. It is about 8""" long, and has a wing expansion of 14'"'", and is 

 yellowish in color, marked with brown. 



The damage which will be done by this insect in this way is not likely 

 to be great. Should they increase enormously and 8i)read to other va- 

 rieties of cultivated corn they may reduce the yield considerably by 

 preventing the fertilization of the female flowers and the " make" of the 

 ears. 



