Asteromyia chrysothamni

Asteromyia clarkei

Asteromyia laeviana

Asteromyia carbonifera

Asteromyia modesta

Asteromyia euthamiae

Asteromyia gutierreziae

Asteromyia x-tortifolia-asteromyia-like-blister

Asteromyia a-carolinianus-asteromyia-like-blister

Asteromyia c-ericoides-asteromyia-like-blister

Asteromyia grindeliae

Asteromyia h-subaxillaris-asteromyia-like-blister

Unknown b-halimifolia-spot-gall

These are usually blue-gray, sometimes buff or with buff markings, 5-15 mm long; elliptical on hosts with wide leaves but elongate with rounded ends on hosts with narrow leaves; usually flat, but sometimes with a swollen appearance. These galls are occasionally found also on the stem. In the galls I have examined, there was only 1 larva/gall.
...
[He lists the following host records for this species, verified by both host and insect identification, most of which are now in the genus *Ericameria*: 
*Chrysothamnus affinis [Ericameria parryi* var. *affinis]*, *C. albidus [E. albida]*, *C. nauseosus [E. nauseosa* var. *nauseosa]*, *C. nauseosus* var. *graveolens [E. nauseosa* var. *graveolens]*, *C. greenei*, *C. plattensis [E. nauseosa* var. *nauseosa]*, *C. viscidiflorus*, *Haplopappus armerioides [Stenotus armerioides]*, *H. bloomeri [E. bloomeri]*, *H. linearifolius [E. linearifolia]*.]
...
[He lists the following additional host species as possible *Asteromyia* hosts based on observations of galls only (no insect material available). They are included on this page based solely on the hosts' current inclusion in either *Chrysothamnus*, *Ericameria*, or near *Stenotus*. These could alternatively represent multiple undescribed *Asteromyia* species or host-range extensions of known species:
*Chrysothamnus depressus*, *C. paniculatus [E. paniculata]*, *C. parryi [E. parryi]*, *C. teretifolius [E. teretifolia]*, *Haplopappus arborescens [E. arborescens]*, *H. cooperi [E. cooperi]*, *Chrysothamnus pulchellus [Lorandersonia pulchella]* - near *Stenotus* (Nesom 2020)]

"The characteristic color of the galls is only in the epidermis, which is 1 cell layer thick. When the epidermis is peeled away, a mat of white fungal tissue can be seen below...hard, black carbonaceous material...encases the larva or larvae."

[He lists the following host records for this species, verified by both host and insect identification: *Aster claytoni [Eurybia divaricata]*, *Aster cordifolius [Symphyotrichum cordifolium]*, *Aster divaricatus [Eurybia divaricata]*, *Aster gracilis [Eurybia compacta]*, *Aster macrophyllus [Eurybia macrophylla]*, *Aster paludosus [Eurybia paludosa]*, *Aster radula [Eurybia radula]*, *Aster spectabilis [Eurybia spectabilis]*, *Aster surculosus [Eurybia surculosa]*]

[Additionally, he lists *Eurybia radulina* as a possible *Asteromyia sp.* host based on observations of galls only (no insect material was available). Included here, provisionally, because the host is in the same genus as most (all?) *A. clarkei* hosts, but these gall records may alternatively represent a distinct midge species.]

"The characteristic color of the galls is only in the epidermis, which is 1 cell layer thick. When the epidermis is peeled away, a mat of white fungal tissue can be seen below...hard, black carbonaceous material...encases the larva or larvae."

[He lists the following host records for this species, verified by both host and insect identification: *Aster choralis* [probably a *Symphyotrichum cordifolium* complex member], *Aster ciliolatus [S. ciliolatus]*, *A. coerulescens* [probably a *S. lanceolatum* complex member], *A. cordifolius [S. cordifolium]*, *A. divaricatus [Eurybia divaricata]*, *A. dumosus [S. dumosum]*, *A. ericoides [S. ericoides]*, *A. falcatus [S. falcatum]*, *A. laevis [S. laeve]*, *A. lateriflorus [S. lateriflorum]*, *A. novae-angliae [S. novae-angliae]*, *A. oblongifolus [S. oblongifolium]*, *A. ontarionis [S. ontarionis]*, *A. paternus [Sericocarpus asteroides]*, *A. pilosus [Symphyotrichum pilosum]*, *A. puniceus [Symphyotrichum puniceum]*, *A. sagittifolius* Wedemeyer *[S. cordifolium]*, *A. schreberi [E. schreberi]*, *A. simplex* [probably a *S. lanceolatum* complex member], *A. undulatus [S. undulatum]*]

[He also lists the following additional *Symphyotrichum* species as possible *Asteromyia* hosts based on observations of galls only (no insect material available). These gall records are included on this page because this midge species seems to specialize on this host genus, but see the "gallformers notes" for possible exceptions to this trend:
*Aster anomalus [Symphyotrichum anomalum]*, *A. azureus [S. oolentangiense]*, *A. elliottii [S. elliottii]*, *A. lowrieanus [S. lowrieanum]*, *A. lucidulus [S. firmum]*, *A. novibelgii [S. novi-belgii]*, *A. occidentalis [S. spathulatum]*, *A. praealtus [S. praealtum]*, *A. sericeus [S. sericeum]*, *A. shortii [S. shortii]*]

[S. canadensis-type]:
"5- to 15-mm diam. when larvae mature, nonmarginal galls round to elliptical, but marginal galls lunate…Color variable: yellow, gray, buff, or purple with a pink center and ringed with white. Strikingly different-colored galls sometimes appear on the same leaf. Circular galls usually contain more than 1 larva but marginal galls typically contain only 1."

[S. juncea-type]:
"circular, about 3-4 mm diam. with only 1 larva/gall. Color dark gray with white or yellow margin becoming dull black or brownish when larva is mature."

[He lists the following host records for this species, verified by both host and insect identification: Solidago angusta [S. petiolaris var. angusta], S. arguta, S. caesia, S. californica, S. canadensis [S. canadensis, S. altissima, and presumably other very close relatives], S. chadonnetii [S. rigidiuscula], S. concinna [S. missouriensis var. extraria], S. confinis, S. curtisii, S. delicatula, S. dumetorum [S. gigantea?], S. elliotii [S. latissimifolia], S. erecta, S. fistulosa, S. gigantea, S. juncea, S. missouriensis [S. missouriensis var. missouriensis], S. mollis, S. nemoralis, S. rigida, S. rugosa, S. sempervirens [S. mexicana, based on location], S. sparsiflora [S. velutina], S. speciosa [S. rigidiuscula], S. squarrosa]

“In typical galls of *A. modesta* there is usually some purple on the gall or on the surrounding area. In the latter case, the tissue immediately above the larva remains green. On *Grindelia* the gall tissue is occasionally hardened but there is no carbonaceous material typical of the other species of *Asteromyia*. There is only 1 larva/gall.”

"…galls are 3-10 mm long; rounded, elliptical, or elongate-elliptical, depending on the width of the affected leaf; and black, usually with a narrow yellow, white, or purple margin…"

"[on S. microcephala [E. caroliniana] and S. tenuifolia [E. caroliniana]] ...the galls are found on the upper green stems in addition to the leaves… usually completely surround[ing] the stem, as in A. gutierreziae… Unlike for A. carbonifera, the epidermis does not peel off the galls in a layer 1 cell thick. Rather, the epidermis is incorporated with the fungi."

 - [on *Baccharis*]: black, 3-4 mm diam.
 - [on *Gutierrezia*]: on stems, black; cylindrical, continuous around stem; about 2-3 times diameter of stem, 5-9 mm long. One larva/gall.
 - [on *Gymnosperma*]: on stems as for *Gutierrezia*. On leaves, they are elliptical; black; 3-5 mm diam.
 - [on *Isocoma [Medranoa]*]: on stems as for *G. microcephala* but smaller, 5-6 mm long.
...
[He lists the following host records for this species, verified by both host and insect identification: *Gutierrezia microcephala*, *Gutierrezia sarothrae*, *Gymnosperma glutinosum*, *Isocoma palmeri [Medranoa palmeri]*.]
...
[Additionally, he lists the following as possible *Asteromyia* hosts based on observations of galls only (no insect material available):]

Following are species on which I have collected galls, presumably of *Asteromyia*, but from which no larvae, pupae, or adults were available for study....
...
*Baccharis halimifolia* L.—Md., Fla.
*B. bigelovii* Gray—Ariz.
*B. douglasii* DC.—Calif.

Following are species on which I have collected galls, presumably of *Asteromyia*, but from which no larvae, pupae, or adults were available for study....
...
*Aster abatus* Blake—Calif.

[This could also represent an extension of a known *Asteromyia* species' host-range to the genus *Xylorhiza*. This page is provided provisionally in case the gall-former on *Xylorhiza* is an undescribed species.]

Following are species on which I have collected galls, presumably of *Asteromyia*, but from which no larvae, pupae, or adults were available for study....
...
*Aster carolinianus* Walt.—Fla.

[This could also represent an extension of a known *Asteromyia* species' host-range to the genus *Ampelaster*. This page is provided provisionally in case the gall-former on *Ampelaster* is an undescribed species.]

Following are species on which I have collected galls, presumably of *Asteromyia*, but from which no larvae, pupae, or adults were available for study....
...
*Aster hirtifolius* Blake—N. Mex.

[This could also represent an extension of a known *Asteromyia* species' host-range to the genus *Chaetopappa*. This page is provided provisionally in case the gall-former on *Chaetopappa* is an undescribed species.]

[In this article Gagné assigns *Asteromyia* galls on *Grindelia* to *A. modesta*, reducing Felt's *A. grindeliae* to synonymy. However, several decades later, his checklist with Mathias Jaschhof (2021) resurrects *A. grindeliae*. In 1968 he listed the following additional *Grindelia* species as possible *Asteromyia* hosts based on observations of galls only (no insect material available). These host records are assigned to this gallformers page tentatively, but could alternatively indicate host-range extensions of other species, or additional undescribed species:
*Grindelia nana [G. hirsutula]*, *G. microcephala*, *G. lanceolata*]

Following are species on which I have collected galls, presumably of *Asteromyia*, but from which no larvae, pupae, or adults were available for study....
...
*Heterotheca subaxillaris* (Lam.)Britt. & Rusby—Fla., N.C.

[This could also represent an extension of a known *Asteromyia* species' host-range to the genus *Heterotheca*. This page is provided provisionally in case the gall-former on *Heterotheca* is an undescribed species.]


Following are species on which I have collected galls, presumably of *Asteromyia*, but from which no larvae, pupae, or adults were available for study....
...
*Baccharis halimifolia* L.—Md., Fla.
*B. bigelovii* Gray—Ariz.
*B. douglasii* DC.—Calif.

A Taxonomic Revision of the Genus Asteromyia (Diptera: Cecidomyiidae)