66 MASSACHUSETTS HORTICULTURAL SOCIETY. 



series of swellings as large as small beans, along the edges of the 

 leaf. A large hemispherical gall at the base of each leaf, is some- 

 times quite abundant ; I have often found them torn open, and 

 empt}'. Probably this may' have been done by birds to get at the 

 lice, or by squirrels, as the red squirrel has been seen to feed upon 

 lice in a leaf-stalk gall of the poplar. 



Our Norway spruces suffer from the attacks of an aphis, the 

 fresh galls of which, green or rosy, and not unlike small cones, 

 appear towards the end of May. They open with little mouths, 

 to let the green flies escape, and in winter the woody, dead galls 

 may be found. In all, I have found about twelve species of aphis 

 galls, five or six of which, made b}- Phylloxera, were upon the 

 hickory. 



A few galls are niade by little moths, which resemble the 

 destructive little creatures that injure our clothing. One of the 

 commonest of these moth galls is to be found upon the stalks of 

 golden-rod, but at this season they are emptj', the moths having 

 come out in the fall. 



I have also found a gall, said to be made by a moth larva, 

 upon the leaf stalks of Populus grandidentata near the Mount 

 Hope railroad station. This gall, which is the size and shape of 

 a small pea, is very common on aspens at Magnolia, and the larvae 

 go underground about the first of October to transform. I have 

 not yet succeeded in rearing them. 



A few galls are made hy beetles. One species causes the 

 grape vine wound gall, and another the raspberry gouty gall. 

 This latter has been found in Dedham. 



Small galls are produced on the leaves of many plants by mites 

 (Phytopi) , — microscopic creatures allied to spiders. Their galls 

 diflTer from insect galls in having an opening below, which is fre- 

 quently lined with hairs. The irritation caused by the gall mites 

 in feeding upon one spot on the leaf, causes there an abnormal 

 multiplication of the leaf-cells, and an arching up of the leaf 

 surface, which in some species is produced into a roundish, and in 

 others into a spindle-shaped gall. 



Some of these mites never produce galls, but their pasturing 

 upon the leaves causes an abnormal growth of hairs, called 

 Erineum. The insects live and breed in this growth, as they da 

 in the galls. I have found about seven species of galls produced 

 by mites, and many kinds of Erineum. 



