Cynips (mellea) sagata, new species
Agamic form
GALL.—As described for the complex. Finally naked, or retaining part of the microscopic, stellate pubescence ; flesh-colored to light brown, with considerable solid matter; rounded or flat basally, occurring singly on leaves.
[Gall description for the complex: A small, globular, thick-walled leaf gall with the larval cell filling most of the interior. Monothalamous ; strictly spherical when fresh and sometimes when dried after maturity, often shrinking irregularly when dried; the gall sometimes drawn out at the point of attachment; the surface of the gall roughly, irregularly shagreened, densely covered with long, white or brown hairs when young (at least in some varieties), the hairs deciduous, leaving a stellate pubescence on older galls; the galls of all varieties finally naked (altho still appearing puberulent because of the shagreened surface; the naked galls whitish, flesh pink or pinkish brown in color; up to 7.0 mm., dried galls averaging about 4.0 mm. in diameter. The thin outer shell re-enforced with a more or less thin, solid mass of crystalline structure; the larval cell highly variable in size, often occupying most of the gall, the wall of the cell hardly differentiated from the solid, crystalline material. Attached to the veins, singly or in small clusters, on the upper or (less often) the under surfaces of leaves of white oaks of all groups.]
HOSTS. — Quercus oblongifolia (types) ; and a tree form of Q. breviloba. In this area, these are the two most abundant tree-forms of white oaks.
RANGE.—Coahuila: Muzquiz, 7 SW, 3600' (Q. oblongifolia, types.) Muzquiz, 5 SW, 3000' (a tree form of Q. breviloba). Probably restricted to the most northern end of the Eastern Sierra of Mexico.
Previously we have described 11 species of this C. mellea complex (see Kinsey 1930, Ind. Univ. Studies 84-86:314-338; and Kinsey 1936, Ind. Univ. Sci. Ser. 4:238-241). All of these are from the southeastern quarter of the United States, except for the one species rydbergiana in the mountains of northern New Mexico. Elsewhere in our Southwest and throughout most of Mexico the complex is replaced by the C. arida complex, and the relations of the two groups are so certain that we never expected to find the mellea complex in Mexico. It is, therefore, an item of some moment to have located a species of this Eastern American group south of the Rio Grande.
This Mexican species, sagata, comes from the northern end of the state of Coahuila, from just south of the Edwards Plateau of Central Texas. Further east in Mexico and in the southeastern corner of Texas, there is a great area of mesquite desert which is an absolute barrier to the interchange of eastern American and Eastern Mexican cynipid faunas. This oak-free area is about 350 miles wide. But there are, nevertheless, some instances of Eastern American affinities in the Eastern Sierra of Mexico; and it took a great deal of field work, spread over many years, to discover that there really are presentday connections between these two faunas. The complete story must be detailed elsewhere. Enough here to record that two of the Central Texan oaks, the live oak, Q. virginiana, and the scrub post oak, Q. breviloba, come close to the border in the neighborhood of Del Rio and a few points further west; that the live oak on the Mexican side is nearly continuous to the border in that same region; and that there is a taller tree (an undescribed species of oak) in the mountains of northernmost Coahuila which is so close to the Texan Q. breviloba that all of its cynipid fauna has Eastern Texan affinities. The present species, C. sagata, is the first of these breviloba relatives to be described from Coahuila.
One additional item of interest is involved in the fact that we have the present species, sagata, from this northern end of Coahuila, from both the Q. breviloba and from the Q. oblongifolia complexes. Oblongifolia is an oak of southern Arizona and northern Chihuahua. It is the only western oak that I have found in the northern end of the Eastern Sierra. Its presence there is probably due to the near approach of the Western and Eastern Sierra in northeastern Chihuahua and northwestern Coahuila. Nearly all of the cynipids on this oblongifolia relative in Coahuila have Western Sierran and Rocky Mountain affinities. The present instance of a cynipid with Eastern American affinities getting onto the western oak is a noteworthy exception to the rule.
The Central Texan species of the mellea complex is as yet undescribed. The galls of that Texan species and of the species from Coahuila are indistinguishable and, it is to be noted, rather distinct from the galls of the Eastern American species of the complex. These galls are, however, close to those made by C. (mellea) rydbergiana, which occurs in the northeastern corner of New Mexico (and adjacent Colorado ? ) ; and the insects of sagata and rydbergiana are closer than either species is to any of the Southeastern American species. In the key to the complex given in Kinsey 1930 (Ind. Univ. Studies 84-86:494- 495), this species sagata would run to rydbergiana. The galls of the two are larger, more strictly spherical, smoother on the surface, and thicker-walled than the galls of any other described species. In all these characters, however, sagata is still closer to the Central Texan species from Q. breviloba.
