D. carbonaria was wrongly associated with leaf blister galls of Asteromyia carbonifera (Osten Sacken), a mistake that was later corrected in Felt (1915), where a good description of the gall was given under D. flavicornis. The galls are composed of two to four leaves that are entwined together and sometimes adhered to each other along their margins to form a loose, elongated structure, usually 3-8 cm in length, without defined chambers, and sticky on the inside. The yellow larvae feed gregariously in the gall and cause feeding spots that resemble those in D. folliculi galls. However, because Euthamia leaves are long and slender, the spots are usually more aggregated than on D. folliculi galls, giving the affected leaves a bumpy or wrinkly appearance. The leaves composing the gall are yellowish green to purplish red, and in the latter case the gall is very conspicuous.

Larvae in enfolded leaves on Euthamia graminifolia...

Galls are green to purple and inhabited by gregarious yellow larvae. Adults of both nominal species were reared in July, so they evidently are at least bivoltine. The two species are probably synonymous. Camptoneuromyia flavescens (Felt) has also been reared from such galls and is probably an inquiline. Host: E. graminifolia.