GALLS. 519 



One of the most curious problems is, to my mind, that of the 

 brilliant colors with which many of these galls are decorated. 

 That the rose bedeguar should be so beautifully adorned with 

 scarlet and green is a fact which does not seem to excite any as- 

 tonishment, inasmuch as it may be said that the colors which 

 ought to have been developed in the petals and the leaves have 

 been diverted from their proper course, and forced to exhibit 

 themselves in the gall. 



Botanists and physiologists will see that this idea is quite 

 groundless, but to the uninstructed and popular mind it has a 

 sort of plausibility, that often commands assent. But when we 

 come to the oak-tree the case is at once altered, and some other 

 cause must be found for the lovely colors of its galls. The cher- 

 ry galls are as bristly colored as any apple, and the soft hues 

 of the oak apple are nearly as beautiful, though not so brilliant. 

 Yet the oak possesses no such store-house of color as is popularly 

 attributed to the rose. Its leaves are simple green, and its flow- 

 erets are so colorless as scarcely to be distinguished by the unas- 

 sisted eye. 



Whence, then, are derived these beautiful colors ? Some hasty 

 observers, who have neglected the first rule of logic, and drawn 

 a universal conclusion from particular premises, have said that 

 the colors of the gall are derived from the insect, adducing as a 

 proof of their assertion the brilliant colors which equally deck 

 the rose bedeguar and the Oynips rosce from which it sprang. 

 But if they had only followed the example of careful naturalists, 

 who, like Dr. Hammerschmidt, have examined and drawn be- 

 tween two and three hundred species of galls, so hasty a gener- 

 alization would never have been made. The cherry or leaf gall 

 of the oak is every whit as gorgeously colored as the bedeguar 

 of the rose, while the insect that made it is quite black. It is 

 true that the diaphanous wings glitter as if they were made of 

 polished gems; but this appearance is due, not to the wings 

 themselves, but to the myriad hairs with which they are regular- 

 ly studded, each hair acting as a miniature prism by which the 

 light is refracted and broken into the resplendent hues of the 

 rainbow. 



Many other trees besides the oak are chosen by certain species 

 of gall-fly, and even the herbs and flowers do not escape the rav- 

 ages of these remarkable insects. The white poppy, from which 



