PLATE 4 



Midge galls 



1 V'ariable twig swellings on wild cherry produced by midge 



larvae working in the subcortical layers, adult not reared 

 la Section of such a deformity 



2 An older type of gall than that represented in i 

 2a An old scar in process of healing 



3 Leaf gall of Lasioptera farinosa Beutm. on black- 



berry 

 3a Early stage of same gall showing reddish discoloration 



4 Irregular twig galls of Cecidomyia citrina O. S., adult 



not reared 



5 Early stage of leaf stem gall on Linden, probably produced 



by Cecidomyia verrucicola O. S., adult unknown. 

 Compare with figures 8 and 8a on plate 2 



6 Globular green gall on Linden leaf. See under 5 



7 Bud gall on Spiraea salicifolia produced by H o r - 



momyia clarkeae Felt 



8 Tubular gall on the under surface of the leaf of C r n u s 



p a n i c u 1 a t a produced by Cecidomyia tuba 

 Stebb., adult unknown 



9 Galls along the under side of the midrib of the bitternut 



hickory produced by C a r y o m y i a c a r y a e c o 1 a O. S. 



10 Enlarged bud gall on Rudbqckia produced by A s p h o n d y 1 i a 



conspicua O. S. 



1 1 Apical bud gall on solidago produced by R h o p a 1 m y i a 



h i r t i p e s O. S. 



12 Midrib swelling on Spiraea tomentosa produced by 



Rhabdophaga salicifolia Felt 



13 Side view of a gall on willow leaf produced by H o r m o m y i a 



verruca Walsh 



14 Cluster of older galls on willow leaf produced b}' H o r - 



momyia verruca Walsh 



15 Flower bud galls on E u p a t o r i u m p u r p u r e u m pro- 



duced byDasyneura purpurea Felt 



16 Fringed terminal bud gall on Spiraea salicifolia, 



adult unknown 



17 Leaf of shadbush, Amelanchier canadensis de- 



formed byHormomyia canadensis Felt 



