Heteroecus bakeri (Kieffer)

Callirhytis bakeri

GALL. — A naked, robust, ovate gall with a slender tip. Monothalamous. Body of gall spherical to more elongate-ovate, more abruptly flattened apically, 9.-13. mm. in diameter, more or less constricted basally; bearing a slender point apically, arising more or less abruptly from the body of the gall, averaging 1.5 mm. in diameter by 5. mm. long; entirely smooth or with a few tubercles, or with part of the surface roughly rugose, or the whole surface granulose; when fresh, bright to dark green, speckled red, or reddish or purplish brown with buff yellow or light green speckling; on aging becoming more uniformly yellowish brown. Internally similar to compacted sawdust, with a cylindrical central cavity extending from the base almost to the tip. Scattered, on twigs of Quercus chrysolepis.

RANGE. — California: Yosemite (Trotter); El Portal, Pasadena, Upland, San Bernardino, San Jacinto Mountain.

I have seen the Pomona College cotypes, and the Baker material in The American Museum of Natural History, and they agree with my Upland material. Indeed, my locality, Upland, and Baker's Claremont, are nearby towns neither of which have Quercus chrysolepis, but these are post office names for very probably the same region in the nearby mountains.

Most of the adults were emerged in the San Bernardino mountains on January 31, 1920, and at Upland on February 3 ; most of the insects were not yet emerged at Pasadena on February 7, and adults were still alive in the galls at El Portal on March 21. As usual, emergence is later in more northerly localities.

Both the galls and adults of this species show considerable variation. The above description applies to an average of the material from Upland, that is, near the type locality. The areolet varies from small to large, the foveae are smooth or sparingly rugose or completely, closely rugose; the parapsidal grooves extend further in some individuals than in others. The galls vary from smooth to very rough or tuberculate, the tip arises very abruptly or only gradually from the body of the gall, the greatest diameter comes at the middle or nearer the apex of the gall. All of these variations occur at each of the localities : San Bernardino mountains, San Jacinto mountains, Upland, Pasadena, El Portal. I cannot perceive any regularity in the concurrence of characters, and have not yet discovered any tendency for a single type to occur in the San Bernardino range, contrary to the usual situation. Galls from Placerville, and part of the material from El Portal, may belong to a northern variety of this species. Some adults from Placerville may belong to a northern variety of bakeri, but unfortunately these galls and adults were not definitely connected in the breeding, and I shall need to see more material before deciding the point.

- Alfred Charles Kinsey: (1922) Studies of some new and described Cynipidae (Hymenoptera)^©

Reference: https://www.biodiversitylibrary.org/page/45387508#page/148/mode/1up