GALL OF AGAMIC FORMS.—Spherical to squash-shaped, hard and crystalline leaf galls, in most varieties bearing short and blunt projecting tips. Strictly or irregularly spherical, or a regular or irregular, inverted, truncate cone; up to 9.0 mm. in diameter, in most varieties bearing short, stout, often crooked and irregular, spiny projections which are in length not half the diameter of the body of the gall; the surfaces of the galls naked or with a puberulence, whitish or light green or pinkish when young, soon becoming (in most varieties) rose violet to coral red in color; internally filled with a compact mass of crystalline material containing a very few branched fibers, the galls soft as rubber when moist, hard and brittle as glass when dry; a more or less complete cavity in the center of the gall below the larval cell and near the very base of the gall, this cavity with the larval cell making the gall appear, superficially, bi-thalamous; the larval cell inseparable, embedded in the compact material of the gall or rarely (particularly in immature galls) held in place by fine, silky, radiating fibers; irregular in shape, up to 4.0 mm. in length, sometimes central in the gall, usually in the upper part of the gall directly under the epidermis, the cell centrally or asymmetrically placed, sometimes extending in part into one of the spiny projections. The gall wholly separable, attached by a point to a vein, usually on the under surfaces, sometimes on the upper surfaces of leaves of Pacific Coast white oaks, Quercus lobata, Q. douglocsii, Q. dumosa, Q. turbinella, and Q. durata.
GALL OF BISEXUAL FORMS.—Spherical, berry-like, very succulent, pale green and more or less translucent when fresh, bright red when very young; the surface smooth or, in some varieties, pebbled and indefinitely marked with low ridges which bear soft, projecting points. The galls 4 to 7 mm. in diameter, shrivelling greatly upon drying, then becoming blackened; when dried upon the twig they become more or less obconical in shape, remaining lighter straw-brown in color. The wall of the gall moderately thin, thinnest apically; entirely hollow inside, without a distinct larval cell. Attached very insecurely by a single, slightly elongated point, on the twigs (bud galls) of probably all the oaks on which the agamic generation occurs; definitely known from only Quercus lobata, Q. Douglasii, and Q. durata.
RANGE.—California, Shasta County to the Mexican border, probably in Lower California.
There are few cynipid galls more abundant than those produced by the agamic forms of echinus in the autumn in California. These galls are confined to white oaks, and do not occur north of Shasta County.
The bisexual forms of echinus, on the other hand, are known from hardly more than a half dozen recent collections, representing, however, four of the six known varieties of the species. These bisexual galls are probably not rare, but they are
