148 



FOREST ENTOMOLOGY. 



6 mm. The alternating species is 6a Andricus noduli (Htg.), which 

 makes galls in the woody portions of young shoots. 



7. Aphilothrix corticis (Linn.) 



The galls of this species are found inserted in the young bark 

 which is formed where the stem has been injured, or in the tender 

 bark which forms in the " healing over " process after a branch' Ihas 

 been sawn off (fig. 141). Sometimes they may be found in clusters, 



Fig. 141. Galls of Aphilothrix corticis in por- 

 tion of bark "healed over by occlusion." 



Fig. 142. Galls of Aphilothrix 

 globuli. 



but as a rule they are distributed over the young bark. It often 

 happens that the rim of under-bark surrounding the cut-off branch is 

 very much torn, and this arises from birds tearing out the galls and 

 lacerating the bark. The flies hatch out in June, and the alternating 

 species, according to Adler, is 7 Andricus gemmatus, a species found 

 in the terminal buds. 



8. Aphilothrix globuli (Htg.) 



The gall (fig. 142) of this species is a beautiful green globular gall, 

 formed in the bud for the coming year. It may be found in Sept- 



