INSECT GALLS OF SPRINGFIELD, 

 MASSACHUSETTS, AND VICINITY. 



BY 



Fannie A. Stebbins, of Springfield, Mass. 



A gall has been variously defined by different authors, but apparently 

 all agree in considering it a deformation or malformation of some part of 

 a plant due to injury inflicted. This injury may be chemical or mechan- 

 ical, and is brought about by the action of fungus, arachnid, insect, 

 character of the soil or fertilizer or cause or causes unknown. The 

 present list includes only those galls caused by insects and the closely 

 allied mites. 



Altho this list is the result of several seasons' collecting, there are 

 undoubtedly many galls which should be found here which have escaped 

 observation, and it seems probable that there are many, especially upon 

 herbaceous plants, which have never been collected and described. 



No part of the plant is free from the presence of galls, they being 

 found upon stem, branch, bud, leaf, flower, fruit and root. They vary 

 in color, size, shape, surface and especially in structure. The simplest 

 consist of little more than a folding or wrinkling of a leaf with an unusual 

 growth of plant hairs and a slight change of size and shape of the cells. 

 At the other extreme may be found such an elaborate structure as the 

 common "oak apple." But they agree in this, that there is always 

 present a portion from which the maker gets food, known as the nutritive 

 section, and another portion which serves as a protection to the maker, 

 the protective zone. 



The effect upon the plant has not been definitely studied in most 

 cases. In many instances no apparent detriment results owing to the 

 comparatively small amount of tissue affected. Some cases are commonly 

 observed in which the persistence upon a plant from year to year of a 

 large number of galls renders it unsightly ; an illustration of this is the 

 gall of Callirhytis punctata on the black and other oaks. But that the 



