Cecidomyia deserta

Hollow, elongate twig swellings, length 1.25 to 2.5 cm.

ex twig swelling gall Celtis occidentalis

Lepidopteron (species undetermined) [this entry is included on the basis of the similarity of the gall; no formal assertion that this is the same species is known]

This gall, (PI. XIX, Fig. 2) is an aborted shoot from a lateral bud, developing very rapidly in the early spring, reaching its full size (in Kansas) toward the end of April. 1.5 ~ 3 cm. long, 4-6 mm. wide. The nodes near the end of the gall bear small leaves which die early. Affected stems either smooth or pubescent. The larva finishes feeding on the central part of the galled twig and leaves the structure during the early part of May. It always eats out a circular hole near the base to make its exit. (PI. XIII, Fig. 2 a). The gall soon after turns brown and drops from the parent branch.

Patton (26) has described a "hollow, elongate, twig swelling" from which he states cecidomyidous flies emerged "about the middle of June." From his brief description it is impossible to state whether his gall is the same as the one here described. The flies noted might have been parasitic on the lepidopteron.

Riley reports a tortricid, Proteoteras aesculana Riley, occurring on the hackberry. No mention of any gall is made, however, in connection with this tree, other than that the larvae were found "on short twigs." On the buckeye and maple it "bores in the terminal green twigs, producing a swelling or pseudo-gall." (See Am. Nat. cit. below). This may be the insect concerned in the production of the lepidopterous gall herewith described, but from this mere suggestion of its gall forming habit, it is impossible to be certain.