Celticecis expulsa Gagne, new species

Hosts: Celtis laevigata, occidentalis

Gall.--On stem, fruit, petiole and base of leaves; irregularly columnar, apically convex or flat, usually with short, central nipple, sometimes 2–3 galls partially coalesced, strongly convex on opposite side of petiole or vein and usually causing leaf distortion; base broad, integral to host tissue, developing apically a circular mark at apex, denoting margin where inner portion of the gall will emerge as a plug from the periphery and dehisce, the remainder of the gall shriveling; green, matte, with sparse white pubescence; 5 mm high, 3 mm broad; the deciduous plug yellow except for green apex, turning brown, larval chamber ovoid, the wall of the plug of uniform thickness.

Biological notes.--The gall of this species is the only one in North America that is not entirely detachable. Initially it appears as a simple columnar elevation of the plant tissue but eventually the interior of the gall surrounding the larval chamber separates as a distinct, hard, cylindrical core (Fig. 21). In due course the outer tissue shrivels, allowing the core to drop to the soil. In Alexandria, Louisiana, and Holland, Texas, galls were evident in early April, already with second instars. Most galls had dehisced by mid-May wherever the gall was found. Adults were reared in March and April, 2011, from galls taken in June, 2009, in Lawrence, Kansas.

Distr.--Galls were found on both northern hackberry and sugarberry. This species may be more widespread than the distribution list indicates, but galls develop and excise earlier in the season than most of our collections were made.

KS, KY, LA, MD, TX, WV

Celticecis expulsa

Celticecis expulsa was found at two study sites in Pennsylvania (Figure 4). This study expands the range of C. expulsa into Pennsylvania, representing a new state record for this species. A limited number of old, woody galls that looked like those of C. expulsa were found at the Phillipsburg study site in New Jersey during this study, suggesting that C. expulsa can also be found in New Jersey. Since actively growing galls with larvae were not found, confirmation of the expansion of the range of C. expulsa into New Jersey was not be obtained

Cecidomyia sp.

Subconical, solitary or compound leaf, stem, petiole or fruit gall with a bluntly truncate, dehiscent larval cell, diameter about 4 mm.

Cecidomyia sp. Cecidium nov.

A gall of the leaves, stem, petiole or fruit occurring generally in an aggregate condition. An isolated specimen on the stem will be described to elucidate the fundamental unit characteristics (PI. XVIII, Figs. 16, 16a). When found singly, the gall is irregularly conic or sub-cylindric, with a very blunt truncate tip. The chief character is involved in the fact that the gall eventually drops its larval chamber enclosed by the nutritive and protective layers. This central part of the gall which slips out has the shape of a short, blunt horn. The tapering of this structure toward the proximal part of the gall makes possible the easy departure of this larva containing portion when the dehiscence layer surrounding it gives way. The gall aggregates commonly occur at or near the end of the stem, the tissue, after the larval chambers have fallen, dying, turning black, giving the twig an unsightly appearance (PI. XIX, Fig. 6). In the case of a single gall (PI. XIX, Fig. 4) the stem is not killed, but the tissue of the "socket" part is cut off by an abscission layer (Fig. 16a, PI. XVIII).

The gall on the fruit (PI. XIX, Fig. 8) possesses exactly the same structure as those on other parts of the plant. The galls shown are not mature, the chamber not having burst through the surrounding supporting tissue. In section (PI. XIX Fig. 4) the galls are seen to project into the ovulary cavity, exhibiting in their entirety the characteristic shape observed in those of the leaf which project from both sides of the leaf. The ovule is aborted.