Druon rusticum Kinsey, 1937, comb. rev.

Druon rusticum Kinsey, 1937: 64, female, gall.
Andricus rusticum (Kinsey): Weld, 1952a.

Gall (Fig. 221). Wool covered, cream-coloured white to tan and russet brown galls; the individual hairs short, straight, hardly covering the larval cells and obviously tufted about each individual cell; making continuous but very irregular, narrowly elongate masses up to 25 mm, average 13 mm long. The larval cells only 1.5 mm long, elongate, 4 to 10 in one cluster.

Biology. Only the asexual generation is known, which induces galls on Q. magnoliifolia (= Q. macrophylla; Section Quercus, Series Leucomexicanae); galls mature in late autumn; adults emerge the following year in April– May (Kinsey 1937).

Distribution. Southwestern Mexico, Guerrero (Kinsey 1937).

Druon rusticum, n. sp.
Agamic form

Gall. — Wool covering cream white to tan and russet brown, the colors often mixed in single dusters; the individual hairs not long, quite straight, hardly covering the larval cells and obviously tufted about each individual cell; making continuous but very irregular, narrowly elongate masses up to 25. mm., averaging nearer 13. mm. in length. The larval cells averaging only 1.5 mm. in length, elongate but less so than usual in the complex, averaging 4 to 10 in a cluster.

Host. — Quercus macrophylla, the largest-leaved oak of the Mexican Cordillera.

Range. — Guerrero: Taxco, 8 NE, 8000k •— Chilpancingo, 6 S, 4000^ — Probably confined to the state of Guerrero in southwestern Mexico.

Life History. — Adults: April 6, 10, 15. May 1.

This insect from Guerrero may occur over a goodly portion of that southwestern states in Mexico. The galls of [rusticum and protagion] are distinct, that of rusticum being mostly tan and russet, with short tufts of fairly straight hairs which make obviously irregular rows along the leaf veins — the galls of protagion being compact and rounded masses of wine purple or purple-brown wool. The parallel development of black, in rusticum and in the Mendelian race of protagion is an instance of similar mutations being involved, in one case in development of a Mendelian race in the midst of the parental species, and in the other case in the formation of a pure population which is a distinct species.