190S ENTOMOLOGICAL SOCIKTV. 48 



THE ECONOMIC IMPOETANCE AND FOOD HABITS OF AMERICAN 



GALL MIDGES. 



By E. P. Felt, Albany, N.Y. 



The extensive and frequently severe depredations of the Hessian-fly, 

 Mayetiola destructor, Say, are too well known to require extended notice in 

 this connection, and the same is also true, though perhaps in a more limited 

 sense, of the Wheat Midge, Cecidomyia tritici, Kirby. The genus Con- 

 tarinia appears to be a very important one to the economic entomologist. It 

 contains the somewhat well known Pear Midge, Contarinia pyrivora, Riley, 

 a species which has been responsible in recent years for the destruction of 

 considerable fruit in Connecticut, New York, New Jersey and presumably 

 in adjacent states. A more recently discovered species is known as the 

 Violet Midge, Contarinia violicola, Coq., a form which has proved a serious 

 enemy of the extensive violet growing industry located in and about 

 Rhinebeck; N.Y., and one that bids fair to cause more injury in the future 

 unless growers are very careful to avoid conditions favorable for its multipli- 

 cation. The Sorghum Midge, Contarinia sorghicola, Coq., another recent 

 discovery, breeds in sorghum seed and, in recent records, has been credited 

 with causing the common failure of this plant to produce a full crop of 

 seed. A still later note states that this insect destroys all sorghum seed in 

 Texas south of a certain line. The Cotton Midge, Contarinia gossypii, Felt, 

 is a species of some economic importance, since it has been reported as 

 injurious to cotton in the British West Indies. Still another form, Con- 

 tarinia negundifolia, Felt, was reared from the leaves of a box elder and is 

 possibly identical with the Cecidomyia jiegundinis, Gill., a species which has 

 been recorded as decidedly injurious to its host plant on the college campus 

 at Ames, Iowa. 



There have been several other injuries by Cecidomyiidae brought to notice 

 recently.- One of these is the extensive destruction of linden buds by a 

 form which we have been unable to rear as yet. This insect was so abundant 

 at Rhinecliff, N.Y., as to destroy from 50 to 75 per cent, of the buds on 

 large trees, causing the death of numerous twigs and of a few large branches. 

 Similar injury to young Catalpa trees has recently been recorded by Prof. 

 Gossard and is probably due to the work of Cecidomyia catalp(B, Comst. 

 Several years ago a small proportion of the grape blossoms in the Chautauqua 

 grape belt were found infested by Cecidomyiid larvae. This last season the 

 insect, Cecidomyia Johnsoni, Sling., was so abundant in an acre of Moore's 

 early grapes near Fredonia, as to destroy from 60 to 75 per cent, of the 

 crop. Observations have shown this pest to be generally distributed through- 

 out the grape belt, and it is very probable that some other mysterious failures 

 of the crop were due to the work of this insect. A number of species are 

 known to live in the buds of plants, and it is presumable that other bud- 

 inhabiting forms, aside from those mentioned above, have caused or are able 

 to cause serious losses. It is certain that members of the Cecidomyiidae are 

 capable of inflicting grave injury, and no scientist can state that any one 

 species might not become destructive in the near future. More knowledge 

 respecting this group is necessary before its economic status can be accurately 

 fixed. 



It is gratifying to state that some species of Cecidomyiidae at least, are 

 distinctly beneficial. The members of the genus Aphidolefes, Kieff., live at 

 the expense of aphids, and are therefore beneficial. One species, A. 



