Page:New species and synonymy of American Cynipidæ.pdf/4

fested galls are usually more or less globular, in groups, but not so completely fused into a single mass as normally. Internally these galls are only loosely woody, with several small larval chambers (without a distinct larval cell-wall) arranged somewhat radially and near the bark. Each portion of the fused mass of the normal gall is woody and will contain toward the center one to three good-sized larval cells with a distinct cell-wall. This is a typical instance of the change effected in the structure of a gall when it becomes inhabited by inquilines. A few other similar instances are well known; it is likely that many others will come to light. A careful study of these might indicate some of the factors which act to produce galls. In A. punctatus the "inquiline" seems to be more truly a parasite, for usually gall-wasps are not reared from galls which breed out the Synergus, nor is the gall-maker's larval cell found to be developed to any size. It is likely that the Synergus does not attack the Andricus larva directly, but indirectly by robbing it of the food in the gall.

Aulacidea abdita, new species
Plate XXI, Figures 6 and 7

Female.—Head and thorax dark piceous (not black), face distinctly rufous, a prominent median elevation on the front, abdomen darkest terminally (not dorsally and basally); areolet moderately large. Head: piceous, the face bright rufous, shading to red or yellowish red at the mouth-parts, coriaceous, with a few short hairs; the face rather irregularly striate, with a moderate median elevation on the face and a separate and prominent median elevation on the front bearing the ocelli. Antennæ 13-(14-)jointed, dark rust-brown, the first two joints reddish brown or bright red; covered with short hairs. Thorax: piceous, usually dark, but not black; mesonotum finely rugoso-punctate, covered with short hairs; parapsidal grooves distinct, continuous to the pronotum, widely separated at the scutellum; median groove distinct for a short distance from the scutellum, its further extension being indistinct to a point one-quarter of the way to the pronotum; anterior parallel lines distinct, extending half the way to the scutellum; lateral lines distinct, extending half the way to the pronotum; scutellum finely rugose with the two small foveæ divergent, widely separate, smooth; mesopleuræ shining, aciculate. Abdomen: shining, smooth, dark red, rufous to piceous terminally, brighter red or yellowish red basally, with a patch of white hairs on each side of the second segment basally. Legs: quite uniformly reddish yellow, the tips of the tarsi slightly darker. Wings: veins brown; areolet distinct, moderately large or large; cubitus hardly reaching the basal vein; radial cell entirely closed; first abscissa of the radius arcuate. Length: 1.5–2.0 mm.

Male.—Similar to the female, but differing as follows: antennæ 14-jointed, third joint curved (but only slightly so), whole antenna reddish yellow, the same color as the legs; median groove less distinct and shorter; abdomen much shorter than in the female, rufous to piceous, and quite dark on the posterior half; wing-veins lighter brown than in the female, the areolet large or very large and elongate on the cubitus toward the basal vein; length, 1.2–1.7 mm.

Galls.—None. The insect lives in cavities (Figs. 6 and 7) in the pith of the stems of Lactuca elongata and most likely of other species of Lactuca. There is no