60 Annals Entomological Society of America [Vol. IV, 



resinicola O. S. and I. resinicoloides Wlms. occur in exuded pitch 

 masses on pine, while I. tritici Kirby is well known as a species 

 of prime economic importance. 



A study of our records from a botanical aspect reveals 

 several facts of interest. We note first that American gall 

 midges live at the expense of some 177 plant genera belonging 

 to 66 plant families. They afford support to some 538 

 species of gall midges representing 44 genera. These forms 

 are known to inhabit 44 fruit (botanically speaking), 14(i bud, 

 218 leaf, 130 stem, and 4 root galls. The paucity of root galls 

 must be attributed in a measure to the difficulty of finding them. 

 In addition to the above some five species were reared from 

 unknown plants and eleven zoophagous species belonging to 

 three genera, making a total of 47 insect genera comprising 

 some 554 species, 441 of these having been reared from either 

 plants or animals. Reference to our records shows that the 

 Compositae supports a very large fauna, 22 of its genera afford- 

 ing sustenance to 118 species of gall midges belonging to some 

 15 genera. The majority of these midges, 55 species occur in 

 bud, o2 in leaf, 30 in stem, while 5 inhabit fruit galls. The 

 Salicaceae, represented only by Salix and Populus, supports 

 some .")'.) species of gall midges referable to 15 genera, by far the 

 greater number occurring upon Salix. As in the Compositae, 

 a large proportion, 21 species occur in bud, 15 in leaf 

 and 21 in stem galls, only 1 living at the expense of 

 the fruit. The Rosaeeae appeal's to be the next plant 

 family favored by gall midges. 10 genera being sub- 

 ject to attack by 4:> species of midges, assignable to 14 

 genera, 3 species inhabiting fruit, 12 bud, 25 leaf and 

 only 3, stem galls. The Gramineae, despite its numerous genera 

 and wide distribution has but 18 genera at present known to 

 support some 25 species of midges representing 12 insect genera, 

 8 species occurring in fruit and 17 in stem galls. This is prob- 

 ably only a small proportion of the forms occurring upon grasses. 

 Our record for the Cyperaceae is even more unsatisfactory, only 

 one species, presumably inhabiting a stem gall being known. 

 The paucity of records in both of these families is probably 

 due to the difficulty of finding the galls. There is a close paral- 

 lelism between the Juglandaceae and the Fagaceae, two genera 

 in each being affected by gall midges. Juglans and Castanea 

 are known to be infested by one and three species respectively, 



