74 Bulletin of the Brooklyn Entomological Society Vol.X 



THE GALL MIDGES OF THE PINE. 



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



The gall midge fauna of the pine has received comparatively 

 little attention, though it deserves careful study, since several 

 species are of economic importance. The object of this brief 

 sketch is to summarize what is known concerning these forms and 

 especially to call attention to the more promising Hues of study. 



The best known of the pine midges is Cecidomyia resinicola 

 O. S., now placed in the genus Retinodiplosis, together with at 

 least three other species, namely, R. resinicoloides Wlms., R. 

 inopis O. S., and an undescribed species, R. palustris. These 

 four species have very similar habits, the larvae of three at least 

 moving about freely in resin which has recently exuded from 

 wounds and probably rasping the living tissues and thus pro- 

 moting, if not causing copious exudations. Small, unthrifty 

 hard pines, Pinus rigida, on the sand plains near Albany fre- 

 quently bear a number of resin masses inhabited by the larvae of 

 R. resinicola O. S., while others showing perceptible, though easily 

 overlooked enlargements of the twigs and smaller branches, may 

 be badly infested and seriously stunted by the larv^ of R. inopis 

 O. S., a species which is primarily subcortical in habit and one 

 which further study may show is more injurious than the better 

 known R. resinicola. The larvae of the western R. resinicoloides 

 Wlms. inhabits pitch masses on the Monterey pine, Pinus radiata, 

 the colonies being most frequently associated with wounds and, in 

 the estimation of the describer, not the primary cause of the 

 exudation. The larvae of the southern R. palustris occur in 

 resin masses on the long-leaved pine, Pinus palustris. We have 

 no data as to the importance of this species. All of the larvae 

 referable to this genus have the posterior extremity bilobed, the 

 tips of the lobes being fuscous, heavily chitinized, and strongly 

 spined, an adaptation which permits the larva to extend its anal 

 spiracles, located in these lobes, through the surface of the viscous 

 resin it inhabits. 



The rock pine, Pinus scopulorum, is subject to attack by a midge 



