192 DIPTERA OF NORTH AMERICA. 



moderate; pedicels between the joints rather short; 9 14-jointed, 

 joints subsessile ; front and mouth pale ; collare with a blackish 

 edge posteriorly, ending on both sides in a short, black streak on 

 the pleuras ; thorax pale, with three broad, almost contiguous 

 blackish or grayish stripes ; the intermediate one is subcuneiform 

 and slightly capillary towards its posterior end, which, for this 

 reason, appears slightly bifid ; it does not reach the scutellum ; the 

 lateral ones are rounded anteriorly, narrowed posteriorly, and end 

 just before the scutellum in a short, black streak, communicating 

 with a brown triangle on the side of the scutellum, so that the 

 latter, being pale itself, is inclosed on both sides by the black 

 streaks and the brown triangles; a couple of black dots are visible 

 on the pleurae ; a pale brown spot on the pectus, between the first 

 and the second pair of coxas ; a brown spot at the basis of the 

 hal teres, which are pale; abdomen reddish, hardly darker laterally, 

 and with a tuft of hair on each side, near the posterior margins of 

 the segments ; legs pale, with a minute, appressed black pubes- 

 cence, which makes them appear blackish; wings immaculate; the 

 second longitudinal vein joins the costal at the apex of the wing 

 or immediately beyond it ; cross-vein indistinct or none. 



2. G. carycecola, n. sp. Gall somewhat larger than the preced- 

 ing, elongated onion-shaped, with the tip prolonged in a point, 

 pale green. Found through the summer either in separate clusters, 

 or mixed with other galls, for instance that of G. holotricha. 



3. G. sanguinolenta, n. sp. Gall conical, narrowed at the basis, 

 blood red or purplish, about 0.15 high and 0.12 broad. I found 

 them for the first time about the middle of July. At this time 

 they were solid inside, except a narrow hollow near the basis which 

 contained the small, somewhat yellowish larva, with a distinct, 

 pointed, spear-shaped breast bone. These galls occur in nume- 

 rous clusters on the same leaflet. 



4. G. tubicola, n. sp. Gall narrow-cylindrical, erect, about 0..15 

 or more long. They break off easily, being inserted in a small 

 protuberance on the leaf, with a sharp-edged socket in the centre, 

 in which the cylinder fits exactly. Their color, when ripe, is more 

 or less brownish, pale greenish at base. They are hollow' inside 

 and contain in October a whitish larva with a breast bone ending 

 anteriorly in a single, elongated point. They generally occur in 

 clusters. Some of these galls are found covered with a viscous 

 fluid. 



