these last six joints being subequal in length. Thorax: mesonotum bright rufous, piceous between the parapsides in their anterior parts, and piceous on the lateral grooves, deeply rugoso-reticulate, with rather long, rather dense yellowish hairs; parapsidal grooves deep, convergent at the scutellum, continuous to the pronotum where they are widely divergent; anterior parallel lines not entirely smooth, extending half the way to the scutellum; median groove evident but largely lost in the rugosities of the mesothorax; the lateral grooves distinct, smooth, and extending half the length of the thorax; scutellum black, somewhat rufous toward the elevated central area, deeply rugose, sparsely hairy, with a broad depression at the base which is similarly rugose, not defining entirely separate foveæ; pronotum and mesopleuræ rufous, shallowly punctate, covered with dense, closely appressed, long hairs. Abdomen: rich rufous-brown, slightly darker in places dorsally and toward the sides of the more posterior segments; hairy on the sides of all the dorsal plates, the hairs longest on the edges of the posterior segments. Legs: bright rufous, the tibiæ very slightly darker except the hind tibiæ which are piceous or black; coxæ rufous; claws toothed. Wings: very clear, only microscopically pubescent; veins brown, the areolet rather large, the cubitus not heavy but extending to the basal vein, the radial cell open, the first abscissa of the radius angulate, almost forming a right angle. Length: 3.5–4.2 mm.
Gall.—A large, dark brown, irregular, woody mass (Figs. 28 and 29) surrounding a small twig. Polythalamous, often containing fifty or more larval cells. The whole is formed of very many distinct but thoroughly fused masses, forming a rather spherical gall 8 mm. more or less in diameter; the surface is very rough, completely cracked as though it were burnt leather, the raised portions polygonal, averaging 2 mm. in diameter, dark, blackish brown, the separating lines being much lighter or yellowish. Internally the gall is composed of a dense, somewhat granular tissue which becomes more compact-woody close to the margin and immediately around the larval cells. The gall is quite too hard to cut through with a knife. The larvel cells are about 3 mm. in diameter, but elongate, and are closely surrounded by the woody tissue; they are scattered quite irregularly throughout the gall. Surrounding the young twigs of Quercus sp.
Range.—Mexico: San Luis, Potosi (Palmer Coll.).
Cotypes.—Ten female and three gall cotypes, in The American Museum of Natural History, the Museum of Comparative Zoology, and in the author's collections. The galls were collected in September 1878 by Dr. Edward Palmer; some of the adults emerged from the galls and others were recently cut out.Dr. Hagen, who received these galls from Dr. Palmer, noted that pupæ and adults were alive in them in October 1879 and also in December 1879, i. e., almost a year and a half after the galls had been collected. It is likely that it is two or three years after the egg is laid before the insect reaches maturity. The tissue of the gall is about as hard as that of any gall I have examined. The species belongs to a group including several Mexican species which produce similar woody galls, and a key to separate these insects was included in the discussion of A. furnaceus, new species. The adult of this species shows some little variation in the shades of the colors.
