Callirhytis piperoides (agamic)

Callirhytis lanata (agamic)

Disholcaspis bassetti (agamic)

Disholcaspis quercusmamma (agamic)

Kokkocynips decidua (agamic)

Amphibolips quercusspongifica (sexgen)

Amphibolips confluenta

Amphibolips quercusostensackenii (sexgen)

Disholcaspis globosa (agamic)

Callirhytis gemmiformis (agamic)

Andricus weldi (agamic)

Andricus quercuspetiolicola (sexgen)

Neuroterus quercusbatatus (agamic)

Amphibolips quercusinanis (sexgen)

Amphibolips ellipsoidalis

Neuroterus perminimus (agamic)

Neuroterus perminimus (sexgen)

Andricus incertus (agamic)

Neuroterus quercusbatatus (sexgen)

Neuroterus fugiens (sexgen)

Neuroterus quercusbatatus (sexgen) (q-bicolor)

Neuroterus quercusbatatus (agamic) (q-bicolor)

Phylloteras rubinum (agamic)

Neuroterus q-alba-white-bead-gall (agamic)

Phylloteras volutellae (agamic)

Biorhiza caepuliformis (agamic)

Dryocosmus cinereae (sexgen)

Dryocosmus quercusnotha (sexgen)

Unknown q-bicolor-acorn-cup-gall

Callirhytis balanacea (agamic)

Callirhytis q-alba-inside-mature-acorn-gall (agamic)

Callirhytis pulchra (sexgen)

Unknown q-velutina-melon-bud-gall

Andricus mamillaformis (agamic)

Callirhytis glomerosa (agamic)

Unknown q-coccinea-tan-bud-gall

Unknown q-coccinea-mottled-gall

Unknown q-coccinea-petiole-swelling

Neuroterus niger (agamic)

Dryocosmus albidus (agamic)

Unknown q-alba-red-hairy-bead-gall

Neuroterus papillosus (sexgen)

Neuroterus escharensis (agamic)

Phylloteras poculum (agamic)

Callirhytis seminator (sexgen)

Andricus foliaformis (sexgen)

Bassettia flavipes (sexgen)

Callirhytis clavula

Diastrophus fragariae

Aprostocetus smilax

Andricus quercusstrobilanus (agamic)

Dryocosmus piperoides

Similar in size and shape [to Andricus dimorphus] but red in color, in an elongated less compact cluster on upper or lower side of large leaves on thrifty shoots of Q rubra, dropping in October. Pubescent under lens. Adults emerged April-May the second spring and some hang over to emerge still later.

Callirhytis lanata

Hemispherical brownish woolly mass on midrib on underside of leaf of Q rubra and velutina. Made up of a cluster of easily detached separate angular galls which drop to the group in the fall in Oct before the leaves, each covered with a dense coating of wool. They are then fleshy and apparently solid as the larval cavity is very minute. Adults emerge the second and third springs in April. 

Disholcaspis bassetti

Bassett's bullet gall. Broadest at the clasping sessile base and tapering gradually above, the apex often lop-sided, 15-20 mm high, the larval cell basal. Single or in crowded clusters on twigs of trees of Q bicolor in fall. Adults emerge in early Oct.

Disholcaspis quercusmamma

Pointed bullet gall. Similar [to Disholcaspis quercusglobulus] but pointed at the apex, subclasping at base, often distorted by crowding and extending along the stem for several inches sometimes. Frequently on sprouts from stumps or on small trees in large numbers in the fall. On Q. macrocarpa and bicolor. Adults emerge Oct. 20-Nov. 10. 

Dryocosmus deciduus

Black oak wheat. Individual galls about size and shape of a kernel of wheat with a fleshy knob at upper end, greenish, smooth, bare. When young concealed in the swelling midrib but later bursting out of a crack in a compact cluster of from a few to 40 galls often rupturing the leaf blade so as to be visible from above, dropping in Oct. On Q. rubra and velutina. Galls collected in Oct. 1916 gave adults Mar. 23-Apr. 22, 1918. 

Amphibolips spongifica

Leaf galls
Large spongy oak apple. Galls appear with the leaves in spring, becoming 40 mm in diameter, green until full grown early in May, turning brown about the time the flies, males and females, emerge the latter half of June. On Q velutina.


Amphibolips confluentus

Leaf galls
Similar [to Amphibolips spongifica] but the adults, all females, emerge in Nov. Probably an alternating generation of the above but the life history needs further study.

Andricus singularis

Smaller oak apple. Diameter 14 mm a third of the sphere projecting from the upper surface of the leaf, the rest on the under side, seldom more than one on a leaf, green, not spotted. On Q rubra in May and June, the adults emerging early in July.

Andricus osten sackenii

Similar [to Andricus singularis] but smaller, diameter about 8 mm, on Q coccinea in June. Adults emerged July 8-15.

Disholcaspis globosa

Individual galls averaging over 7 mm in diameter.

Globular bullet galls with a distinct inner cell often free in an irregular cavity within. Up to 40 in a cluster at base of sprouts from stumps of Q alba. Adults emerge in late Oct and early Nov.

Callirhytis gemmiformis

Conical, greenish becoming brown when mature, 3-4 mm high, from weak dormant buds on limbs or from adventitious buds on trunk of large trees of Q alba in Sept and Oct. Deciduous. Adults emerge the second spring, transforming the fall before.

Cynips weldi

A globular cluster, 8-20 mm in diameter, on under side of petiole at its junction with the leaf blade, consisting of a dozen or more reddish brown galls, closely pressed together, tuberculate at the distal end, flattened at the sides, tapering to the point of attachment, dropping to the ground in late Sept or Oct before the leaves. On trees of Q alba. The emergence of the flies is in March or early April and distributed over a period of five or six years, none probably appearing until the second spring. 

Midrib or petiole swellings
Oak petiole gall. Somewhat globular, conical above with a depression at apex, hard, green, polythalamous, the larval cells radiating out from the center. On the petiole or basal part of midrib, usually several in close proximity on the tree. In May and June, the adults emerging in late June. On Q. alba, bicolor, and macrocarpa.

Agamic gen. of Neuroterus batatus (Fitch)

Stem galls.
In winter a similar [to N batatus sex gen] but woody gall covered with normal brown bark, the adults emerging the latter half of April and ovipositing in the buds.

Amphibolips inanis

Larger Empty Oak Apple. Green with scattered purplish spots, 18-32 mm in diameter, produced singly on under side of the leaf of Q rubra. Adults emerged June 11, June 25, and July 6 in different seasons.

Amphibolips ellipsoidalis

Bud galls.

Cylindrical, 5 by 14 mm, tapering toward the blunt ends, mottled. In early spring from weak lateral buds on Q palustris and imbricaria. Deciduous. The fly probably emerges early the next spring as one was found dead in breeding cage April 10.

Neuroterus perminimus

Cells separate, numerous, elliptical, 1-2 mm long, showing on both sides of the leaf but more distinct on upper. On Q alba in June [sexgen] and similar galls in the fall [agamic]. Flies emerge from the overwintering galls April 1-23.

Andricus incertus

Fimbriate cup gall. A smooth elongated gall, 4 by 7 mm., partly imbedded in a fimbriate depression in the side of the acorn cup and slipping to the ground when mature in the fall. On Q. bicolor. Flies emerge the second and third springs Mar. 25-Apr. 18 and oviposit in buds of Q. bicolor. Alternating generation unknown. 

Sex. gen. of Neuroterus batatus (Fitch)

Stem galls.
OAK POTATO GALL. Irregularly fusiform, tuber-like stem swellings, 10-40 mm. long by 15 mm. in diameter, deforming the terminal twigs of small trees or sprouts of Q. alba.
In spring at base of the new growth, fleshy, green, glaucous, the adults emerging the latter half of June.

Neuroterus fugiens

Cells lenticular, adjacent to a vein in rows, more conspicuous on lower side which is covered with sparse rosy hairs, the wall thinner above. In early spring when leaves are one-third grown on Q macrocarpa. Adults emerged May 30. 

Sex. gen. of Neuroterus noxiosus (Bass.)

Midrib or petiole swellings.
NOXIOUS OAK GALL. Fleshy smooth green swellings of midrib on under side causing the leaves to curl. Developing with the leaves in early spring, full grown during June, adults emerging June 12-July 3. On Q. bicolor. 

Agamic gen. of Neuroterus noxiosus (Bass.)

Stem galls.
NOXIOUS OAK GALL. Irregular woody enlargement at or near the ends of twigs on trees of Q. bicolor, up to 40 mm long by 25 mm in diameter, covered with normal bark, polythalamous, conspicuous on the trees in winter. The adults emerge in early April and oviposit in the buds just as they are beginning to swell.

Biorhiza rubina

Spherical but depressed, pure white, bare, 3-4 mm in diameter. On under side of leaf of Q alba in the fall, dropping before the leaf. Adult probably emerges the second spring.

Undetermined species

Galls less than 5 mm in diameter
Globular, pure white, bare, smooth, 1.5 mm in diameter, scattered on under side of leaf of Q alba in the fall.

Undetermined species

Spangle gall. Concave above with no papilla in center, convex below without ring-like ridge, covered with whitish bloom, 3 mm in diameter. On Q bicolor and macrocarpa in August. Not reared.

Biorhiza caepuliformis

Clustered at base of vigorous sprouts, up to 30 in a group, onion-shaped, 5-8 mm long, pointed at apex, longitudinally striate, brown, hard and brittle when mature in the fall, monothalamous. Often enclosed in a "shed" by ants which are fond of the honeydew the growing galls secrete. On Q rubra and velutina. Adults emerge in the late fall, Nov 23-Dec 2.

Diplolepis cinereae

Hemispherical sessile blister

Hemispherical, slightly elongated, sessile by its flat face on the lower side of leaf of Q rubra in spring. Greatest diameter 6 mm, wall very thin, green, veiny and translucent. Flies emerge about the last of May.

Diplolepis notha

Elongated, pointed blister at edge [of leaf]

Elongated, blister-like, at edge of leaf, the conical tip prolonged on upper side of leaf into a sharp point, the walls very thin, green, veiny and translucent. In May on Q rubra, velutina, and coccinea. The flies emerge early in June.

Undescribed species

Cell in the tissue of the cup and not separable from it directly underneath the acorn causing it to become lopsided. On Q bicolor in the fall.

Undescribed species

On Q velutina and rubra in fall on acorns of the current season. Globular, green to tan, 3-4 mm in diameter.

Undetermined species

On Q alba. Similar, less common [to Callirhytis lapillula: On Q bicolor. Cells in a group of as many as 15, shaped like apple seeds, underneath or slightly to one side of the cotyledons, causing the acorn to bulge somewhat on one side. Occurs in fall in large acorns. Flies issue Apr 25-May 16 the second and third springs.]

Pea-shaped, smooth, green, bare, fleshy, scattered in small numbers along the flower axis, dropping with the flowers in late May or early June. Contain 4-5 cells. Flies emerge early in June of the same season. On Q rubra and coccinea.

Undescribed species

Melon-shaped, with longitudinal grooves like some types of cantaloupe, 3-4 mm, rose-pink, with a small tuft of hairs at the apex. On Q velutina. Found but once-on May 1. Not reared.

Undetermined species

Similar [to A mamillaformis] on Q bicolor and macrocarpa in the fall.

Undetermined species [tentatively presumed to be the same gall later named C glomerosa]

Similar [to Andricus mamillaformis] on Q rubra in the fall

Undetermined species

Similar [to [Andricus mamillaformis](https://www.gallformers.org/gall/842)] on Q coccinea in early spring, smooth, polished, tan-colored, scarcely protruding.

Undetermined species [unlike other undescribed species in this source, Weld does not list this species in his 1959 book]

Found under large trees of Q. coccinea in May and probably bud galls. Globular, slightly compressed, with a scar and short stalk at base, a linear indentation at the apex, no nipple, 3 by 4 mm., brownish or purplish, mottled. 

Undetermined species

Swollen base of the petiole of Q imbricaria, 6 mm long by 2 mm in diameter, remaining attached to the twig during the winter.

Undetermined species [tentatively associated with N niger. N niger isn't otherwise listed in this source.]

Cells separate but in more or less definite rows along the midrib or a main vein, more prominent on upper side, a faint papilla in center below, round in outline, about 1.5 mm. in diameter. Exit hole on the lower surface. On Q. alba in the fall. 

Undetermined species [tentatively associated with D albidus]

Similar [to Phylloteras rubinum], depressed, pure white, 4 mm in diameter on under side of leaf of Q coccinea in fall, dropping in October.

Undetermined species

Globular, red, finely pubescent with a scar at apex, 1 mm in diameter, very numerous on under side of leaf of Q alba in fall.

Neuroterus papillosus Beut. 

Cells isolated, more prominent on upper surface, scarcely projecting below, elliptical in outline, 1 mm. long, very numerous on leaf, exit hole below. On Q. bicolor in June. Adults emerge the last of June. 

Neuroterus escharensis

Stem galls
Cells in the twigs, no deformation evident
Cells in the tissue of the twig under leaf scar, the tip protruding so slightly as to be scarcely visible until the adult begins to chew its way out in the latter half of April. Sometimes two cells under the same leaf scar. Near the terminal cluster of buds on Q bicolor.

Xystoteras poculum

White oak spangle gall. Button-shaped, 3-4.5 mm. in diameter, with a heavy rounded ring of tissue on under side between pedicel and rim, concave above with a slight nipple in center, covered with a whitish bloom. In large number on under side of leaves of Q. alba, dropping in the fall. The flies emerge in late March the second spring. 

Callirhytis seminator

A globular or elongated woolly or spongy white mass often tinged with spots of pink, 20-30 mm. in diameter, consisting of numerous slender fusiform bodies attached by one end to a common point on the twig —probably a bud gall morphologically. Each seed-like body contains one larval cell and the distal part bears the white filaments. Occurs on trees of Q. alba, starting about the middle of May, the adults emerging June 29-July 12. 

Andricus foliosus

Slight local thickening of midrib on leaf of Q. bicolor with a rosette of leafy bracts both above and below. Green, fleshy, containing 1-6 cells, only one on a leaf, usually on the basal third, first appearing in May when the leaves are about one-third grown. Adults emerge in late June. 

Callirhytis flavipes

Smooth fusiform swelling along midrib of Q. macrocarpa in spring. Green, fleshy, polythalamous, the adults emerging about June 20. 

Callirhytis clavula

Oak club gall. Terminal, club-shaped, about 15 mm. in diameter with several leaves growing from it, containing one to three larval cells. Green while growing but becoming brown and woody after the escape of the adults in early July, the old galls persisting for years. On trees of Q. alba. 

Diastrophus smilacis

Strawberry petiole gall. A cylindrical gall on the petiole of a leaf, 20-60 mm. long by about 5 mm. in diameter, containing 8-20 cells, red in summer, turning brown later. Flies emerged June 2, 1918. 

Diastrophus smilacis

Described as irregularly rounded, abrupt pithy swellings on stem, one inch long by one-half inch in diameter. Polythalamous. Described from Chicago in 1896 and not collected since. Specimens much desired. It is suspected that there is an error here in the identification of the host plant. The adults are said to have emerged in Jan. and Feb. but the type flies in the National Museum bear the date label of May 1-8.

Cynips strobilana O S 

Globular cluster, up to 35 mm. in diameter, at end of twig, consisting of 25 or more wedge-shaped bodies attached by their tapering bases to a common point on twig. Hard, breaking off easily when mature, brown, monothalamous, dropping in the fall. Some flies emerge in the spring for at least three seasons. On Q. bicolor and macrocarpa. 84. 

Cynipid Galls of the Chicago Area