GALLS FOUND NEAK BOSTON. 67 



I wish particularly to call attention to a certain point in the 

 history of our oak gall insects which offers a wide field for inves- 

 tigation and discovery. 



"When Dr. Adler was pursuing his investigations with regard to 

 the growth of galls of Cynipidte, he made the startling discovery 

 that the insect which came from a gall did not resemble the one 

 that made the gall, and the gall that it made did not resemble the 

 gall that it came from. That is, each gall insect resembled it& 

 grandparents and not its parents, and the gall that it produced 

 resembled those produced by its grandparents. So unlike was 

 the gall-fly to its parent, that they had been described as belong- 

 ing to different genera. He thus reduced thirty-eight species to 

 nineteen, and found only four species where this alternation of 

 forms did not occur. Male and female gall-flies will occur in one 

 brood, while in the succeeding brood females only are to be found. 



There is no reason wh}- the oak galls of this country should not 

 show similar phenomena, and indeed this has been found the case 

 with certain species observed by Mr. Bassett. One afternoon in 

 1864, visiting a thicket of shrub-oaks {Querciis ilicifolia), Mr. 

 Bassett found hundreds of the gall flies which come from the 

 wooU}' " operator " galls of the same plant, ovipositing between 

 the cups of the young acorn and the little acorns themselves, and 

 later in the season, he found that the galls which were produced 

 resembled seeds or kernels of corn, projecting somewhat from the 

 cup. Mr. Bassett has also discovered an alternation of forms in 

 the galls of Cynvps noxiosa, on Quercus bicolor, which form large, 

 woody, terminal or sub-terminal swellings on the twigs of this oak. 

 These galls develop in summer, and the insects, which are all 

 females, live in the galls over winter, coming out before the leaves 

 appear in the spring ; when the leaves appear a gall grows oa 

 them, which is an enormous development of the midrib of the leaf, 

 often to the extent of an inch in diameter, and an inch and a half 

 in length. The gall-flies come out about the 20th of June ; long 

 observation has convinced Mr. Bassett that the insects which 

 come from one of these galls produce the other gall. 



In the last number of " Psyche," Mr. Bassett describes a recent 

 discovery which he has made : 



"One of our most common gall insects here in Connecticut i» 

 Callirhytis futilis, O.-S. The galls appear in early summer in 

 great numbers on the leaves of Quercus alba; they are in the 



