Gagne Description ²

Common, found on Eucarya hickories; single or clustered, on lower leaf surface between veins; height 1.9—4.1 mm, conical, basal edge flared, acute or rounded, the base adjacent to leaf either flat or convex, the central part of the base permanently hard and differing in texture from softer outer part (Fig. 136), lateral sides of cone in profile convex at first, becoming concave, then furrowed upon further drying, the apex obtuse to acute; hairless, green, turning brown, crimson, or purple, not sticky; base with shallow, circular, central excavation, the leaf without exfoliation around connection; larval chamber ovoid, located at base of gall, surrounded by yellowish pellicle different in texture from the soft, large-celled usually purple tissue beyond that partly collapses with age; a bundle of fibers present between apex of larval chamber and gall apex. Galls of C. sanguinolenta and C. conoidea are most similar to one another in shape, but that of C conoidea bears short, rigid, sparse hairs.

Gagne Biology Note ²

Tiny, green, occasionally red galls with first instars were found as early as midMay in the Washington, DC area. By mid-June, both small and full-size galls were present with first and second instars, respectively. Small galls with first instars could still be found as late as early August, although the preponderance of galls found after mid-July contained second instars. Third instars were found beginning in early August and by late August most galls contained third instars. Galls remain on leaves until leaf drop in October. Many galls are red or purple by autumn but some remain green. Pupae escape through a hole made in the base of the gall, to the side of the central, harder part (Fig. 136).

Sources and Credits

1. (c) Adam Kranz, all rights reserved, uploaded by Adam Kranz
2. (c) Adam Kranz, some rights reserved (CC BY-SA)

More Info

• iNat taxon page
• Animal Diversity Web
• Biodiversity Heritage Library
• BOLD Systems BIN search
• BugGuide
• CUIC Insect Images
• Field/Photo ID for Flies
• Global Biodiversity Information Facility (GBIF)
• Guide to Hickory Midge Galls
• Guide to Hickory Midge Galls
• Maryland Biodiversity Project
• NatureServe Explorer 2.0
• Systema Dipterorum

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