Atrusca cubitalis (Kinsey, 1936)

Figs 207–220

Synonymy
Cynips (dugesi) cubitalis Kinsey 1936: 107, female, gall.
Atrusca cubitalis (Kinsey): Weld 1951: 638.

Types examined

HOLOTYPE female Cynips cubitalis (dugesi) “Durango Colo. 12N Gall 8.27.29, 1 fm. 11.4.29”, “Q. gambelii, Kinsey coll.”, red “Cynips cubitalis, Holo- Paratype”, deposited in AMNH, NYC, examined by GM. Three PARATYPE females “Durango Colo 12N galls 8.27.29, females 11.9.29”, “Q. gambelii Kinsey coll.”, red label “Cynips cubitalis Paratype”, deposited in the general collection in AMNH, NYC, examined by GM.

Gall (Fig. 220)

The gall is similar to all galls of the dugesi and bella Kinsey’s complexes. Mature galls light rosy tan, unspotted, shining, up to 22 mm, with average 16 mm in diameter.

Biology

The asexual generation is only known to induce leaf galls on Q. gambelii. Galls mature in autumn, first adults emerge in October–November.

Distribution

USA: Colorado.

Cynips (dugèsi) cubitalis, new species
agamic form

GALL.-Similar to all galls of the C. dugèsi and C. bella complexes. Mature galls light rosy tan, unspotted; often shining; of moderate size, up to 22. mm., averaging nearer 16. mm. in diameter. Figure 52.

HOSTS.—Several oaks of the Q. Gambelii complex.

RANGE.-Colorado: Glenwood Springs. Aspen, 6 E. Gunnison, 20 W (galls only). Colona. Ouray, 3 S. Durango, 12 N (types). Mesa Verde. Lewis. Utah : Monticello, 10 E (galls only). La Sal (galls only). Probably restricted to an area in the Rocky Mountains west of the Continental Divide, known from Western Colorado and easternmost Utah. Figure 18.

LIFE HISTORY.—Larvae: August 23 to September 2, in most cases too young to breed. Adults: October 29, November 4, 6, 9, 20, 21, 24.

This short-winged species, cubitalis, is the producer of all the oak apples found in Colorado west of the Continental Divide. There is no species of the Cynips bella complex in that area. On the eastern slopes of the Colorado Rockies oak climbs hardly above 6,000 feet, falling some 4,000 feet short of most of the passes. On the western slopes, another oak of the Gambelii complex climbs much higher, reaching to about 9,500 feet, although it also falls short of the passes. The Western Colorado cynipids are, in consequence, well isolated from the Eastern Colorado species by a considerable oak-free area which extends over the Divide and well down on the eastern slopes of the range. Cubitalis is best distinguished by its nearly closed areolet and by the fusion of the marks in the cubital cell which form a line parallel to the cubital vein. Although the insect is in other respects hardly separable from brevipenmata, the characters noted are constant throughout the several localities, well distributed over the western half of Colorado, from which we have bred insects.