76 The Ottawa Naturalist. [Aug. -Sept. 



GALL MIDGES AS FOREST INSECTS. 



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



The minute gall midges or Itonididae have been practically 

 ignored by the forester and, taken as a group, little is known of 

 their economic importance under average woodland conditions. 

 The larger, frequently abundant deformations produced bv the 

 gall-making wasps, Cynipidae, and the sawflies, Tenthredinidae, 

 are relatively much better known, though it is probable that 

 they are of less economic importance. 



Numerous gall midges, referable to the Lestreminae and 

 Heteropezinae, live as larvae in decaying woody tissues and 

 materially hasten the process of disintegration. Species of 

 Miastor and Oligarces inhabit the inner bark of various trees in 

 incipient stages of decay, while some species of Monanita, such 

 as M. lignivora Felt have been reared from the fungous affected 

 heart-wood of pine and undoubtedly hasten decav. Some 

 Epidosariae inhabit dead, mostly dry, woody tissues. 



All of the foregoing species are of less importance than the 

 gall-making forms infesting living trees. The deformations of 

 the latter may be conveniently classified according to the part 

 affected. 



Seed of fruit-inhabiting midges, such as Dasyneura canadensis 

 Felt, may destroy a considerable proportion of seed in spruce 

 cones. The same is true of Oligotrophus heiulae Winn, and birch 

 seed, while //on /t/a catalpae Comst. infests Catalpa pods and is a 

 pest of some importance. Whitish, flower-shaped, fungoid galls, 

 probably a btid and possibly a fruit deformation, are numerous 

 in some parts of the South on Bald Cypress, Taxodium distichum, 

 and are caused by Itonida anthici Felt. The extent to which 

 fruit infestation may go in this group is shown by the rearing 

 of seven species from the fruit of various wild cherries. 



Bud galls are produced by many species and usually mean 

 the death of the affected part, or at least a rest:ltant deformation. 

 The Catalpa midge, mentioned above, not only infests the seed 

 pods but destroys the greenish tips and produces stunted, com- 

 paratively worthless trees. Phytophaga ulmi Beutm. and 

 Dasyneura ulmea Felt infest lateral and terminal buds of elm 

 sprouts and occur somewhat abundantly, though their injuries 

 have not as vet been considered of much practical importance. 

 The Box Elder in the West suffers from the attack of two gall 

 midges, namely, Cecidoniyia negundinis Gill., a bud-inhabiting 



