Cynips (aggregata) aggregata (Weld)
agamic form
Diplolepis aggregata Weld, 1926, Proc. U.S. Nat. Mus. 68 (10): 15, fig. 3. Kinsey, 1930, Ind. Univ. Studies 84–86: 446. Houard, 1935, Marcellia 28: 99.
“Cynips howardiana Kinsey in litt., possibly C. plumbea Weld” Hoffmeyer, 1930, Ent. Meddel. Kbhvn. 17: 214.
Andricus aggregatus Hoffmeyer, 1933, Ent. Meddel. Kbhvn. 18: 247.
GALL.-Large, up to 33. mm., averaging nearer 28. mm. in diameter, with a slender, drawn-out, sharply-pointed pedicel at base; light pinkish to rose and light russet brown, often finely spotted (never striped), sometimes with a whitish or bluish puberulence; occurring singly or (more often) in large clusters; the galls inserted in cracks in the bark of young twigs. Figures 87, 89.
HOSTS.—Quercus oblongifolia, Q. arizonica, Q. sacame, Q. diversicolor [rugosa] (?), Q. grisea, Q. toumeyi (the last record acc. Weld 1926).
RANGE.-New Mexico: Hillsboro (galls, Q. grisea). Arizona: Globe. Safford (galls, Q. arizonica). Fort Grant (galls, Morrison acc. Weld 1926). Oracle (Q. arizonica, Kinsey coll. Also acc. Weld 1926, and also Holloway in Kinsey coll.). Sabino Trail in Santa Catalina Mts., 4000' (Q. oblongifolia, Q. arizonica, Q. diversicolor. Also Weld coll., and types, Chrisman coll.). Santa Rita Mts. (Q. oblongifolia, Q. ari zonica). Whetstone (Q. arizonica). Tumacacori Mts. (galls., acc. Weld 1926). Fort Huachuca (galls, Q. arizonica. Also Jacot acc. Weld 1926). Chiricahua Mts. (Q. arizonica, Weld and Hubbard, acc. Weld 1926). Pata gonia (galls, Q. tourneyi, acc. Weld 1926).
Apparently confined to the oak-inhabited mountain ranges of South eastern Arizona and Southwestern New Mexico. Figure 84
LIFE HISTORY..—Adults: Alive in gall November 26. Emerging November 5, 22, 27. Also before December 3, after January 1, on January 11, and on later dates. An insect cut from a gall on November 26 was still alive in a pill box on December 31 (acc. Weld 1926). The bulk of the emergence probably early in January.
This is the only species of the complex known from the United States. It is found only in the southeastern quarter of Arizona and in the immediately adjacent portions of New Mexico. On all of the evergreen white oaks in that area, the stem galls of aggregata are conspicuous objects forming clusters two thirds as large as a man's fist. My own collections of the species were made in 1919, but it is difficult to understand why the species was not collected earlier and described before 1926.
Aggregata finds its closest relative in C. finitima, which occurs in the adjacent state of Chihuahua, in Mexico. From finitima, aggregata is to be distinguished by having a gall which is unspotted or only finely spotted with purple. The differences between the two insects are not great but enough, especially when fortified by the gall characters, to indicate that two populations are isolated in the two regions.
