Andricus incertus
(agamic)agamic:The agamic (AKA unisexual) generation of an oak gall wasp (cynipini) species consists of only female wasps, which do not mate before laying the eggs which become the male and females of the sexual generation (sexgen).
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The gall's range is computed from the range of all hosts that the gall occurs on. In some cases we have evidence that the gall does not occur across the full range of the hosts and we will remove these places from the range. For undescribed species we will show the expected range based on hosts plus where the galls have been observed.
Our ID Notes may contain important tips necessary for distinguishing this gall
from similar galls and/or important information about the taxonomic status of
this gall inducer.
Gall.--This fimbriate-cup gall on bicolor was well described by Riley in 1877 along with a similar one but protruding farther, from a smooth cup on Q. prinoides. Both have often been referred to in literature frequently under the names glandulus and glandulosus. The fly described as Andricus glandulus Beutenmueller, of which the author has a cotype, and associated with the above gall is a red species from an unknown gall. It belongs to the genus Callirhytis and is closely related to C. operatola — the agamic generation of C. operator (Osten Sacken).
Habitat. — The type material was collected at Wilmette, Illinois, September 1, 1917, when the galls were dropping to the ground. "When some of the galls were cut open just a year later about half still contained larvae and half pupae and adults. One fly emerged in cage March 25 and one April 18, 1919. On December 2, 1919, five living flies were cut out. Transformation thus occurs in fall and emergence in the spring and the emergence is distributed over two seasons. As the emergence is before flowering there must be an alternating generation in a vernal gall. In 1908 the galls had nearly finished dropping by September 9 and in 1912 they had all dropped by September 10. They have been seen also at Evanston, Kenilworth, and Glencoe, Illinois, and at Porter, Indiana. The herbarium at Shaw Botanical Garden, St. Louis, has a specimen from Kimmswich, Missouri, collected in 1860.
The writer has field notes on a similar gall on nine other white oaks of the eastern United States where the recess in which the gall rests is not fimbriate and the gall protrudes half its length or more. See plate 3, figure 12, on prinus [montana] and figure 13 on macrocarpa. As he has not been able to rear any of these as yet it is not known whether any or all of these are caused by the above-described species or which if any is glandulus Beutenmueller.
