276 Berg. D. Walsh on the Insects inhabiting the Galls 



twig, had evidently "slopped over," so to speak, when she came to the 

 terminal leaf-bud, and had laid a few eggs in the base of the embryo- 

 leaves of that leaf-bud. The consequence was that, when the galls 

 reached their full growth in the following August, there were a few 

 strung along at considerable intervals on the base of one or two of those 

 leaves, that had developed from the terminal leaf-bud since the es^s 

 were laid in the preceding autumn. Here, then, if anywhere, we might 

 expect to find a change in the characters of these wrongly-located galls, 

 produced by mistake in a part of the tree where naturally they had no 

 business to be. But what was the fact ? In every one of these five 

 or six cases they were precisely like the outlying galls of a normally loca- 

 ted mass of Q. ficus galls, differing only from the central ones in being 

 round and not many-sided. They were alike in color, alike in texture, 

 alike in containing internally a mass of very fine, woolly, interlaced fi- 

 bres, with a central cell located close to the short peduncle of the gall; 

 (for these galls are not " hollow," as is incorrectly stated by Fitch and 

 re-stated by Osten Sacken ;) finally they were precisely alike in size. 

 Yet, as the change in location in this example was the greatest possible, 

 namely, from a twig to a leaf, here, if anywhere, we might have ex- 

 pected some little variation in the aberrant gall. Is it likely, then, 

 that when the change in location is merely from one part of a leaf to 

 another, namely, from the footstalk to the leaflet, we should meet with 

 fundamental differences in the structure and size of the same identical 

 gall, as we must assume to be the case, if we assume that carysecaulis 

 Fitch and caryee globuliWalah are produced by one and the same spe- 

 cies of Aphidae? Moreover, carysecaulis is comparatively rare 

 near Rock Island, Illinois, and caryee globuli very common, while on 

 the contrary Dr. Fitch found carysecaulis very common and was en- 

 tirely unacquainted with caryee globuli. 3rd, An iuquilinous Saw- 

 fly — Nematus hosjies n. sp. — which inhabits a Willow-gall made by a 

 Gall-gnat, is undistinguishable from a true gall-making Saw-fly — Ne- 

 matus s. pomum n. sp. — which I have bred very extensively from a 

 well-marked Willow-gall. (See above, p. 261.) 4th. Nematus quer- 

 cicola, n. sp. (see above, p. 260), which is iuquilinous in a Cecido- 

 myidous bud-gall on the White Oak, positively cannot be distinguish- 

 ed, when the two are placed side by side, from Nematus s, pisum n. sp., 

 which makes a leaf-gall on Salix discolor. 5th. Many specimens of 

 another inquilinous Saw-fly — Euura perturbans n. sp. — which I have 

 reared from a variety of different galls made by Gall-gnats, are abso- 

 lutely undistinguishable from specimens bred by myself of the gall- 



