FIRST ANNUAL REPORT OP THE STATE ENTOMOLOGIST. 



173 



THE SOLIDAGO GALL UOTK—Getec/ua gallcesolidaginis, N. Sp. 

 —PL 2, Figs. 1 and 2. 



Every body must have noticed the large round galls about the 

 size ot a walnut which are found upon the straight smooth stem of the . 

 common Golden-rod (Solidago nemoralis). Thero are sometimes two 

 on the same stalk and they are most conspicuous in winter time when 

 the leaves are off the plant. Upon cutting open one of these galls it 

 is found to consist of a pithy solid mass, in the centre of which is a 

 olump white footless maggot. This maggot in due time develops into 

 a two-winged fly, which was long since described by Dr. Fitch asTry- 

 pela (Acinia) solidaginis. 



The gall which I am now about to speak of, occurs on the same 

 species of Solidago, and in almost equal abundance with the former, 

 though its architect has never hitherto been described. This gall 

 which is represented at Figure 96, b, is of a 

 very different form from the preceding, being 

 altogether more elongate and narrower, and 

 upon cutting it open it is found to be hollow, 

 and to contain, instead of a white footless mag- 

 *got, a gray 16-footed caterpillar (<?), which in time 

 .„ develops into the little moth which is repre- 

 snted with ; expanded at Plate 2, Fig- 



ure 1, and ;s closed at Figure 2. 



history of t] may be thus briefly 



The moths winter over and may be seen 

 flying. ay, in which mo 



iptured a specimen. When the 

 nts of the Golden-rod are abou 

 inches high the noth deposits an egg 



I, or at the side of the 

 stalk j e worm hatching 



the egg works into the stalk, and causes it to 

 swell by gnawing and thus inducing the secretions towards it. By 

 the beginning of June the gall has just begun to form and at this time 

 upon cutting it open the worm at -J grown, and its 



excrement is as yet all at the upper portion of the gall. As the plant 

 grows, so the gali increases in size, remaining, however, at the same 

 altitude from the ground. By the middle of July both the gall and 

 its maker have attained their full size, and upon opening the former 

 at this season of the year the excrement will be found packed closely 

 at both its ends, and from the small quantity of such excrement (d) to be 

 found, it would appear that all but the more solid parts had been ab- 

 sorbed by the plant, it probably acting as a manure to stimulate the 

 growth of the gall. When full grown, the worm measures rather 

 more than half an inch, and it now prepares for changing into the 



