Antron quercusnubila (Bassett, 1881), sexual generation

Synonyms: Cynips quercusnubila Bassett (1881b: 56), females and galls. Dryophanta nubila combination and corrected spelling by Mayr (1881); Dryophanta nubila combination by Ashmead (1885: 296); Diplolepis quercus-nubila combination by Dalla Torre and Kieffer (1910); Cynips nubila combination by Cresson (1923); Diplolepis nubila combination by Weld (1926); Cynips (Acraspis) nubila var. nubila combination by Kinsey (1930); Antron nubila combination by Weld (1951); Antron quercusnubila corrected spelling by Burks (1979). Kinsey (1930, 1936, 1938) included 10 additional species in his “nubila” complex, found on a range of Mexican oaks: Cynips (Acraspis) chica Kinsey 1936; Cynips (Acraspis) incompta (Kinsey, 1920); Cynips (Acraspis) nigricula Kinsey, 1936; Cynips (Acraspis) radialis Kinsey, 1936; Cynips (Acraspis) rufula Kinsey, 1936; Cynips (Acraspis) russa Kinsey, 1930; Cynips (Acraspis) subtincta Kinsey, 1936; Cynips (Acraspis) tincta Kinsey, 1936, Cynips (nubila) lanaris Kinsey, 1938 and Cynips (nubila) molucrum Kinsey, 1938.

Cynips (Acraspis) russa Kinsey, 1930, syn. nov.. Kinsey (1930) originally used the species name Cynips nubila russa and mentioned that he found the female to be indistinguishable from the female of C. nubila. The galls are also identical to those of A. quercusnubila and the two taxa share the same host oaks (Q. arizonica, Q. oblongifolia) and geographic distribution (Arizona, Santa Catalina Mnt., from Tucson to Globe). Later, Kinsey (1936) put Cynips nubila russa into the genus Cynips subgenus Acraspis, nubila complex, named as Cynips (nubila) russa. Weld (1952a) treated it as Cynips nubila russa Kinsey. Weld (1960) in his Cynipid Galls of the Southwest listed only Antron nubila, and did not even mention A. russa. In Burks (1979) it is a valid species, Antron russum (Kinsey, 1930). The other nine species of Kinsey’s Cynips nubila complex, all occurring in Mexico, are considered valid species by Pujade-Villar & Ferrer-Suay (2015).

Biology. Asexual galls (Fig. 79) develop on leaves, sexual galls in lenticel buds; both generations on Q. arizonica, Q. rugosa and Q. oblongifolia.

Distribution. USA: Arizona (Burks 1979).

Antron nubila

Quercus arizonica, oblongifolia, toumeyi, reticulata [rugosa], subturbinella [turbinella]
Leaf galls
Detachable
Fig 86. Wool crimson, in fall.

Diplolepis nubila

Cynips quercus nubila
Andricus incomptus Kinsey [Kinsey's later work treats incomptus as a variety of Cynips nubila, but reverses Weld's synonymy to maintain incomptus as a distinct variety]

Nubila was described from an unknown oak from Mule Pass Mountains, Ariz., the galls collected in November. The writer has collected galls in several localities in Arizona and on several hosts. The species seems to be most common on Q. arizonica and galls were taken at Bisbee, in Chiricahua Mountains (flies emerging January 2). in Ramsey Canyon in Huachuca Mountains, at Patagonia, in Tumacacori Mountains (flies out of January 13, February 6 and 10), in Santa Rita Mountains and at Oracle in Santa Catalina Range. Galls collected at Oracle December 17, 1921, gave adults December 31. January 3, 4, 10, 12, 14, 16, 22, 23, 24, and February 6. The forest insect collection has galls from the Santa Catalinas from which adults emerged March 30, 1916. Galls on Q. toumeyi were collected in the Patagonia Mountains on December 12, 1921, and flies emerged January 13 and 24 and February 4. The flies from arizonica range from 2.6-4.6 mm. Average of 58 specimens 2.88 mm. Those from toumeyi average smaller but all measured were within the range of the arizonica series. The writer collected the galls on Q. oblongifolia in the Huachuca, Patagonia, Santa Rita, and Santa Catalina Mountains and at Nogales but reared no adults. The galls were noted also on Q. reticulata in the Santa Catalina Mountains. Incomptus was described from two adults cut out of galls of an unknown oak at San Luis Potosi, Mexico. The writer has examined both, comparing one directly with a Basset type of nubila. As the galls were collected in September it is the writer's idea that at that time the nutritive layer had not been all used up and the larva had vitality to transform into an undersized adult but not enough to chew its way out of the hard gall. Never having been exposed to light and open air it is much paler than flies that emerge normally. Had it darkened up normally the two adjacent spots near the apex of the wing might have become connected into one double one as is the case in nubila, a series of which shows considerable difference in the amount of fusion that has taken place in the spots, due either to fluctuating variation or to the length of time that has elapsed or amount of exposure to light since emergence from the gall. If a nubila wing were bleached somewhat it would present the condition seen in incomptus.

Cynips quercus nubila, n. sp.

Galls: Densely hairy, sub-globular or hemispherical clusters of galls on the under side of leaves of an unknown species of oak; always on the midvein. When fresh the hairs are of a fine deep crimson, but fade somewhat in drying. At the base they are yellowish white. The galls in each cluster grow from the same point on the leaf, and the clusters are from one-half to one inch in diameter, and contain from one to five or more galls or larval cells. The cells, denuded of their covering of hairs, are nearly globular, tapering, however, to an obtuse point at the end attached to the leaf, and they measure from three-sixteenths to nearly or quite half an inch in diameter. The shell is about .02 of an inch in thickness (thicker than this at the base, however) and is very hard and brittle when dry; it contains no larval cell, and its inner surface is slightly roughened as if gnawed.

These galls, in their dense hairiness and in their size and outward appearance, resemble closely those of C q. tenuicornis n. s. from the same locality; but while in this species the larval cells are separate, in tenuicornis they are enclosed in an envelope of a dry porous consistence. The fine crimson color, seems to be a constant character of C q. nubila, and the insects from the two galls are widely different.

Antron quercusnubila
(Cynips quercusnubila)*

Hosts: Quercus arizonica, oblongifolia, toumeyi, turbinella

Unlike those of other woolly galls, the hairs on the galls of this species are appressed or matted.

Cynips (Acraspis) nubila
agamic forms

GALL. — A mass of coarse hairs, containing a spherical, hard core. Monothalamous, the core averaging 4.0 to 7.0 mm., the entire gall averaging 10.0 to 15.0 mm., compacted clusters of several galls measuring up to 24.0 mm. in diameter. The central core strictly spherical except where drawn out basally at the point of attachment; the surface of the core crystalline, very rough, scurfy, covered with short, straw-colored, crystalline hairs among which are the close-set, long, fine, hair-like spines which form the tangled, woolly covering of the gall, these spines up to 8.0 mm. in length, unbranched, wavy. The central core hard, crystalline, brittle, with an outer wall fully 1.0 mm. in thickness; all of the rest of the core (up to 5.0 mm. in diameter) is hollow, the inner walls being rough, irregular, without any other larval cell. Occurring singly or, more often, in clusters of two to five galls, the clusters usually more or less hemispherical but sometimes more elongate when containing several galls; attached to the mid-veins, on the under surfaces of the leaves of Quercus arizonica, Q. oblongifolia, Q. Toumeyi, Q. reticulata, Q. glaucophylla) , and probably other related oaks.

RANGE. — Known from Arizona and central Mexico. Probably widespread in Mexico, and to be expected in southwestern New Mexico. Figure 58.

The gall of this species is one of the most attractive in the genus Cynips. The tangled mass of brilliantly colored, hair- like spines covering the spherical core marks the gall at some distance in the field. In collecting in January (1920) in the Santa Rita Mountains of southern Arizona, I camped at four thousand feet among trees on which nubila galls were common. A mountain storm had banked these evergreen oaks with wet snow, offering a background against which the wine-purple galls appeared too fantastic to be real anywhere but in the enchanted lands of our Southwest.

The galls of the Arizona varieties probably appear early in the summer; they are full-grown by September, and the adults probably mature in another month or so. The insects, however, do not emerge until late in December or in January, during a season of cold weather and snow. Perhaps the more southern, Mexican variety, incompta, has a different life history.

While nubila is common in Arizona south of Globe, it has not yet been recorded from north of there or from New Mexico. If must be very rare in these latter regions if it occurs in them at all.

While the hairy gall of this species appears superficially different enough from the galls of most Cynips, it is nothing but a villosa gall with the spines much lengthened. The spines are inserted on the surfaces of the two in the same way, in two varieties of nubila they are enlarged basally, quite as they are in villosa, and in both species they are surrounded basally by peculiar, short, crystalline hairs. The resemblances are so striking that, once having seen them, one wonders why they are not apparent at first glance.

[Kinsey describes three varieties of this species; only Andricus incomptus is listed separately. See paper for details on the other two.]