Atrusca rubella, n. comb.

Cynips (arida) rubella, new species
Agamic form

GALL.—Similar to other galls of the complex. Mature galls more or less hemispherical, with a broadly flattened base, shrivelling considerably so gall is usually irregular in shape ; light red or purple brown in color, with some white scurf ; up to 7.0 mm., averaging near 5.5 mm. in diameter.

HOSTS. — Quercus intricata, (types) ; Q. cordifolia [striulata]. The first is a shoulder-high scrub white oak, the second, the lowest dwarf oak of the region. Replaced on Q. Pringlei in the same area by C. conspecta.

RANGE.—Tamaulipas: Miquihuana, 7 SE, 6000'(Q. intricata, types. Also on Q. cordifolia [striulata].) Not yet known beyond this one locality in the southwestern corner of Tamaulipas, in a central portion of the Eastern Mexican Sierra.

This is one of the two species representing the arida complex near Miquihuana, in the southwestern corner of Tamaulipas. See the discussion under the other species, C. conspecta, in the present paper. As noted in that discussion, rubella is found on Q. intricata and Q. cordifolia, while C. conspecta is found on Q. Pringlei in the same area. The two cynipid species are not closely related. Rubella is most closely related to the species saxifera and saxulum. Saxifera also occurs in the Eastern Sierra of Tamaulipas, just east of the locality from which we have rubella. Saxulum is a widespread species in the Western Sierra of Mexico, from southern Chihuahua through Durango.