488 



AMERICAN FORESTRY 



addition to the unknown chemics of the process, the gall- 

 causing instinct is one of the most mysterious things in 

 entomology." 



Galls of various forms and sizes are gathered from 

 many different kinds of trees indigenous to many coun- 

 tries. Thus in commerce we have the Chinese galls, the 

 Bokhara galls, 

 and so on. The 

 best galls yield 

 from sixty to 

 seventy per 

 cent of gallo- 

 tannic acid, and 

 are known as 

 the white, the 

 green, and the 

 blue galls, and 

 the oaks are 

 great producers 

 of them. Some- 

 times the irri- 

 tation caused 

 by the pres- 

 ence of the lar- 

 va is responsi- 

 ble for their ex- 

 istence, while, 

 as a rule, they 

 are produced 

 by a virus de- 

 posited by the 

 female when 

 she places her 

 egg. In .\sia 

 Minor, Syria, 

 Persia and in 

 adjacent coun- 

 tries, a special 

 species of oak 

 ( Quercus i- 

 fectoria) 

 grows abund- 

 antly and furn- 

 ishes the great- 

 est number of 

 galls for the 

 trade A species 

 of Cynips is 

 responsible for 

 their produc- 

 tion, and this ' 

 insect deposits its eggs in the tender shoots of the tree. 



We are informed by an authority at hand that "galls 

 are inodorous, and have a nauseously bitter and astring- 

 ent taste. They are nearly spherical, and vary from the 

 size of a pea to that of a hazelnut. When good, they are 

 of a blue, black or deep-olive color. They are also 



LEAVES OF MAPLES SHOWING RED AND YELLOW SPOTS 



Fig 6 So thick are these ocellated gall-spots on the leaves of some maples that they 

 destroy the leafage of the, entire tree ; a tree so affected may be recognized at a consider- 

 able distance. Insert cuts : F and G, Gall on goldenrod made by SoUdago gall-moth, a, open- 

 ing; c, larva; d, burrow. C on G opening seen from in front. Redrawn by the author 

 from Riley. ,0 



termed ntttgalls or gallnuts." According to some British 

 authorities, one of whom is cited in the Encyclopaedia 

 Britannica (XII., 574), "in the autumn (also on oak 

 leaves) are found those curious flat brownish galls com- 

 monly called 'oak spangles,' which by many are taken 

 for fungi and have indeed been described as such." And 



it was Tenny- 

 son who said, 

 in his poem on 

 "The Talking 

 Oak :" 



"I swear (and 

 else may in- 

 sects prick 



Each leaf into 

 a gall) 



This girl, for 

 whom your 

 heart is sick, 



Is three times 



worth them all." 



Lutz, in his 



useful little 

 work referred 

 to above, pre- 

 sents us with 

 some eighty- 

 six cuts, giving 

 various exam- 

 ples of those 

 galls we find 

 on such trees 

 and plants as 

 the conifers, 

 the poplar and 

 Cottonwood, the 

 willow, hickory 

 alder, oak, elm, 

 hackberry, the 

 witch- hazel, 

 tulip-tree, ma- 

 ple, sumac, rose 

 raspberry and 

 b I a c k b e r ry, 

 Crataegus, cin- 

 quefoil, wild 

 cherry, grape, 

 touch - me - not 

 linden and 

 basswood, 

 hue kleberry, 

 wild lettuce, 

 goldenrod and 

 ash. They are 

 extremely characteristic and instructive, and as arranged 

 on the plates, not readily mistaken for another. 



Further on I will give some of these growths, repro- 

 duced by my camera from the actual specimens ; but only 

 a few can be thus presented, for the fact must ever be 

 borne in mind that simply hundreds of these curious 



