[Neolasioptera] eregeroni. Widespread eastern Nearctic. Conyza canadensis (Asteraceae).
Diplosis eregeroni Brodie 1894a: 13. Canada: Ontario, Toronto; ST; A,L; USNM.
Diplosis erigerontis Aldrich 1905: 162, error for eregeroni.
Cecidomyia erigeroni Felt 1925c: 54, missp. of eregeroni.

Galls found on Erigeron canadense, variously situated from base of stem to tips of branches of flowering panicle; galls irregularly cylindrical, tapering at both ends, spindle-form, those on the branches more or less spherical; from 1 to 15 galls on a plant, seldom more than 10; found usually on diminutive plants, such as grow on wet, sandy places or on high, dry banks.
...
The galls appear like swellings of the stem or branches, uniform in color with the plant, the surface with feint longitudinal lines, slightly elevated ridges and ragged transverse elevations, resembling leaf scaurs. The interior consists of uniform, soft, white pith, through which the larvae tunnel.

Neolasioptera eregeroni [induces] an inflorescence gall [specifically] a smaller, harder gall [than N. erigerontis] on branches of the inflorescence [of Erigeron canadensis. The gall] appears ..., in fall, is monothalamous and usually about 10 mm long by 5 mm in diameter.

[Below is a less truncated version of the above quotation]
Two different kinds of stem galls occur on this host: a large, more or less soft, pithy gall near the base of or midway up the stem and a smaller, harder gall on branches of the inflorescence... [The second] appears much later, in fall, is monothalamous and usually about 10 mm long by 5 mm in diameter...Larvae from the two kinds of galls show a few minor differences, but adults have not been reared from the inflorescence gall. If the two galls are shown to be made by two separate species, Brodie's name, N. eregeroni, would be available for the inflorescence gall. Brodie wrote that some larvae escaped from the galls, which is not known in Neolasioptera, but the adults he reared do belong to Neolasioptera. Host: C. canadensis. Distr.: Massachusetts to Ontario, south to Maryland, and Nebraska and California.

[Note: See Brodie's publication for more notes; it is actually unclear from his publication whether he reared adult midges from the lower, larger galls or the upper, smaller galls. The adults emerged from late May to early June. His published notes indicate a mixed collection, possibly including galls from the previous year's inflorescences.]