Druon protagion (agamic)

Druon receptum (agamic)

Druon flocculentum (agamic)

Druon fullawayi (agamic)

Druon garciamartinonae (agamic)

Druon hansoni (agamic)

Druon ignotum (agamic)

Druon ignotum (sexgen)

Druon linaria (agamic)

Druon pattoni (agamic)

Druon q-potosina-like-flocci (agamic)

Druon quercusflocci (agamic)

Druon quercuslanigerum (agamic)

Druon quercuslanigerum (sexgen)

Druon rusticum (agamic)

Druon serretae (agamic)

Striatoandricus furnessae (agamic)

Striatoandricus furnessulus (agamic)

Striatoandricus guatemalensis (agamic)

Striatoandricus tenuicornis (agamic)

Druon alexandri (agamic)

Druon gregori (agamic)

Druon protagion Kinsey, 1937, comb. rev.

Druon protagion Kinsey, 1937: 61, female, gall.
Druon polymorphae Kinsey, 1937: 60, female, gall, syn. nov.
Druon malinum Kinsey, 1937: 58, female, gall, syn. nov.
Andricus polymorphae (Kinsey): Weld, 1952a: 308.
Andricus protagion (Kinsey): Weld, 1952a: 309.
Andricus malinum (Kinsey): Weld, 1952a: 307.

Gall (Fig. 138). Compact clusters of cells (most often 3–4, sometimes more) covered with short, compact, brownish-yellow, russet, or bright purplish-brown woolly pubescence that darkens with age; pubescence usually covering the individual larval cells, although the tips of the cells are sometimes exposed; single clusters circular, closely compact, averaging around 10 mm in diameter and 8 mm high, but larger agglomerations of clusters oval or more elongate and up to 30 mm long. The larval cells rather stout but elongate, averaging about 3.0 mm long.

Biology. Only the asexual generation is known, which induces galls on Q. rugosa (= Q. conglomerata), Q. potosina and Q. polymorpha (all Section Quercus, Series Leucomexicanae); galls mature in late autumn, adults emerge from February of the following year, with most emerging in March–April.

Distribution. Mexico: Michoacan, San Luis Potosi, Tamaulipas.

Druon receptum Kinsey, 1937, comb. rev.

Druon receptum Kinsey, 1937: 62, female, gall.
Andricus receptum (Kinsey): Weld (1952a)

Gall (Fig. 209). Greyish yellow-brown wool covering a cluster of 4 to 8 larval cells (Kinsey 1937). Pubescence darkens with age; the individual hairs are very long, considerably tangled, completely hiding the larval cells. The individual clusters are rounded to oval, dense but fluffy, averaging nearly 20 mm in diameter and 12 mm in height. Several individual clusters can be fused into large, elongate masses up to 35 mm long. Mature larval cells are over 3.5 mm long on average, rather robustly elongate (Kinsey 1937).

Biology. Only the asexual generation is known, which induces galls on Q. rugosa (= Q. rhodophlebia) and Q. potosina (both Section Quercus, Series Leucomexicanae) in Mexico; Q. rugosa in Arizona. Galls mature in late autumn; adults emerge from February of the following year, most emerging in March–April.

Distribution. USA: Arizona, Santa Catalina Mtns. Mexico: Guanajuato, Mexico City, Querétaro, State of Mexico, Zacatecas.

Druon flocculentum (Lyon, 1996), comb. nov. 

Andricus flocculentus Lyon, 1996: 181, female, gall.

[No photo of the gall is included.]

Gall. Clustered but discrete cells forming a woolly mass on the underside of the leaf midrib (Lyon 1996). Clusters ranging from 3 to 6mm in diameter, the pubescence is white to pale yellow. The individual cells are 2.5–3.0 mm long, ovoid and thin walled. 

Biology. Only the asexual generation is known, which induces woolly leaf galls on Q. pungens and Q. obtusata (both Section Quercus, Series Leucomexicanae). Galls were collected in February-March. Adults probably emerge shortly afterwards.

Distribution. USA: TX (Lyon 1996); Mexico: Mexico City in this study.

Druon fullawayi (Beutenmüller, 1913), comb. nov

Andricus fullawayi Beutenmüller, 1913: 244, female, gall

Gall (Figs. 31–32). Brown, elliptical, thin-walled, unilocular, with reticulate surface, covered with long soft 
rusty brown woolly fibers. Gall 5–8 mm in diameter, found singly or in groups of two to many galls on the upper side of the leaf, along the midrib, cluster usually beginning at the base of the leaf. The long, soft hairs distinguish this gall from all other hairy leaf galls on white oaks.

Biology. Only the asexual generation is known, which induces leaf galls on Q. garryana, Q. douglasii, Q. lobata (Section Quercus, Series Dumosae). Galls do not dehisce from their host leaf, instead falling to the ground with the leaves in autumn; adults emerge in March of the following year.

Distribution. USA: California (Burks 1979) and Mexico: Zacatecas.

Druon garciamartinonae, Cuesta-Porta, Melika & Pujade-Villar sp. nov. 

Gall (Fig. 45). Creamy fluffy gall on the midrib on the underside of leaves, pubescence sometimes with purple areas. Cluster of a few cells.

Biology. Only the asexual generation is known, which induces woolly leaf galls on Q. glabrescens (Section 
Quercus, Series Leucomexicanae). Galls mature in October; adults emerged in April under laboratory conditions.

Distribution. Mexico: State of Mexico, San Felipe del Progreso, Plateros-Arenales.

Druon hansoni Pujade-Villar, sp. nov. 

Gall (Fig. 68). Brown fluffy gall on the midrib on the underside of leaves, cluster of a few cells. 

Biology. Only the asexual generation is known, which induces woolly leaf galls on Q. oleoides (Section Virentes). Galls mature in April; adults emerged shortly afterwards under laboratory conditions.

Distribution. Costa Rica: Guanacas, Parque Nacional Santa Rosa.

Druon ignotum (Bassett, 1881), comb. nov. 

Cynips ignota Bassett, 1881: 106, female, gall. 
Andricus ignota (Bassett): Ashmead, 1885: 295.
Dryophanta ignota (Bassett): Ashmead, 1887: 127.
Diplolepis ignota (Bassett): Dalla Torre & Kieffer, 1910: 360. [NOT Diplolepis ignota Osten Sacken, 1863]
Rhodites ignota (Bassett): Dalla Torre, 1893: 127. [NOT Andricus ignota Bassett, 1900 (junior homonym).]
Diplolepis ignota (Bassett): Weld, 1926: 26.
Andricus ignotus (Bassett): Weld, 1951: 634.

Gall. Asexual galls (Fig. 99). Small (2–3 mm long) brown, thin-walled and gregarious ovoid galls firmly attached to the underside of the leaf midrib in clusters of up to 30 or more. The entire cluster is covered with a dense coating of long woolly hairs, which is initially cream-coloured or pink but fades to brown over the winter, and sometimes wears away. 

Biology. Alternate asexual and sexual generations are known (see comments). See Bassett (1881) and Weld (1926) for the biology of the asexual generation. Asexual galls have been recorded on leaves of Q. bicolor and Q. macrocarpa (Section Quercus, Series Prinoideae), mature in October–November, adult females emerge very early the following spring (late March to late April in Edmonton, Alberta, Canada), often on the first warm days after accumulated snow has melted and fallen leaves bearing galls are exposed. Emerged females fly up to buds and oviposit. The sexual generation adults emerged in Edmonton in early June. Females were observed ovipositing multiply along the midrib on the upper leaf surface in a zipper-like pattern, suggesting that asexual females in a given gall cluster are sisters. Galls of the asexual generation first became apparent on leaves in Edmonton in late July.

Distribution. USA: Massachusetts, Connecticut, Illinois, Minnesota (Burks 1979), Nebraska (Weld 1926); Canada: Alberta, Manitoba.

Druon ignotum (Bassett, 1881), comb. nov. 

Cynips ignota Bassett, 1881: 106, female, gall. 
Andricus ignota (Bassett): Ashmead, 1885: 295.
Dryophanta ignota (Bassett): Ashmead, 1887: 127.
Diplolepis ignota (Bassett): Dalla Torre & Kieffer, 1910: 360. [NOT Diplolepis ignota Osten Sacken, 1863]
Rhodites ignota (Bassett): Dalla Torre, 1893: 127. [NOT Andricus ignota Bassett, 1900 (junior homonym).]
Diplolepis ignota (Bassett): Weld, 1926: 26.
Andricus ignotus (Bassett): Weld, 1951: 634.

Gall. Sexual galls (Fig. 100) occur singly or in groups in buds of Q. macrocarpa. They are apparently undifferentiated ovoid cells approximately 2 mm long, integral within buds and young growing shoots, and cause little or no visible external deformity or damage. Galls are generally only detectable by the emergence holes left by the adult insects.

Biology. Alternate asexual and sexual generations are known (see comments). Asexual galls have been recorded on leaves of Q. bicolor and Q. macrocarpa (Section Quercus, Series Prinoideae), mature in October–November, adult females emerge very early the following spring (late March to late April in Edmonton, Alberta, Canada), often on the first warm days after accumulated snow has melted and fallen leaves bearing galls are exposed. Emerged females fly up to buds and oviposit. The sexual generation adults emerged in Edmonton in early June. Females were observed ovipositing multiply along the midrib on the upper leaf surface in a zipper-like pattern, suggesting that asexual females in a given gall cluster are sisters. Galls of the asexual generation first became apparent on leaves in Edmonton in late July.

Distribution. USA: Massachusetts, Connecticut, Illinois, Minnesota (Burks 1979), Nebraska (Weld 1926); Canada: Alberta, Manitoba.

Druon linaria Kinsey, 1937, stat. rev., comb. rev. 

Druon linaria Kinsey, 1937: 57, female, gall. 
Andricus linaria (Kinsey): Weld, 1952a: 306

Gall (Fig. 112). Creamy white furry leaf galls in clusters (usually of 3 or fewer galls) on the underside of leaves, at the base of the leaf, yellowing a bit with age. Individual hairs on the gall are straight, not long. Each cluster closely compact, circular, up to 9 mm in diameter, 3 mm high.

Biology. Only the asexual generation is known, which induces woolly leaf galls on Q. oleoides (Section Virentes). Galls mature in late autumn; adults emerge in February–March of the following year. 

Distribution. Mexico: Eastern Sierra Madre Oriental, Tamaulipas (Kinsey 1937).

Comments. Pujade-Villar et al. (2016) erroneously synonymized this species under A. quercuslanigera (Ashmead). After revising the type material, both species are transferred to Druon and we consider D. linaria and D. quercuslanigerum to be two independent valid species with distinct morphological differences. 

Druon pattoni (Basset, 1881), comb. nov.

Cynips pattoni Bassett, 1881: 98, female, gall. 
Andricus pattoni (Bassett): Weld (1952a).

Gall (Fig. 124). Fluffy, orange-brown woolly leaf galls on the underside of the leaf midrib, containing clusters of larval cells oriented perpendicularly to the leaf surface. The cells are completely hidden by short, dense pubescence. The largest clusters often extend for more than half the length of the midrib. Found on young trees, most often on leaves near the apex of strongly growing shoots. The galls resemble in their woolly covering those of D. quercusflocci (Walsh), but the latter are round rather than often elongate, with longer woolly hairs, and that species is only found on Q. alba.

Biology. Only the asexual generation is known, which induces galls on Q. chapmanii and Q. stellata (= Q. obtusiloba) (Section Quercus, Series Stellatae). Galls mature in October–November; adults emerge shortly afterwards under laboratory conditions or in February of the following year in the field.

Distribution. USA: Connecticut to Florida, Oklahoma, Texas (Burks 1979). 

[In Druon quercusflocci: comments]

A sample of galls on leaves collected from Aguascalientes State (Mexico) on Quercus potosina produced two adults morphologically resembling D. quercusflocci. The galls have a completely whitish woolly covering over clusters of 2–6 seed-like distinct larval chambers attached to the midrib of leaves (Fig. 150, right). The galls of D. quercusflocci from USA are densely pubescent, mainly orange-brown with some scattered white wool (Fig. 150, left). The internal structure of distinctly separated larval chambers is shared by both of these gall morphologies. The adults from Mexico differ slightly from typical D. quercusflocci by the following mesopleural and mesoscutellar characters. [...] We consider these differences insufficient to define two separate species, but the phenotypic differences in gall traits may indicate that the Mexican specimens belong to a different species. Alternatively, the differences may result from host plant effects on gall structure, as seen in some other oak cynipid galls with a wide host range (e.g. asexual generation leaf galls of Cynips quercusfolii Linnaeus, 1758 in the Western Palaearctic, which are smooth when developing on Quercus robur L. but covered with raised tubercles when developing on Q. petraea (Matt.) Liebl.). Thus, we have not officially assigned the Mexican specimens to D. quercusflocci and await more material and further evidence, such as molecular data

Druon quercusflocci (Walsh, 1864), comb. nov. 

? Cynips Quercus-lana Fitch, 1859: 814, adult, galls (see comments)
Cynips quercus flocci Walsh, 1864: 482, female, gall. 
Cynips (Andricus?) flocci Osten Sacken, 1865: 352. 
Andricus flocci (Walsh): Mayr, 1881: 28.
Andricus quercusflocci (Walsh): Burks, 1979: 1087

Gall. (Fig. 150). Woolly, dirty white to pinkish pubescent galls, 10–12 mm long, 8.0–8.5 mm broad and 4–5 
mm high, containing 2–10 seed-like larval chambers attached at one end to the midrib on the upper or lower side of the leaf; the cluster of galls is usually elongated along the direction of the leaf midrib. The larval cells are distinct individually, rather than fused into a single mass, 0.2–1.0 mm in diameter, and covered with short crystalline hairs.

Biology. Only an asexual generation is only known, which induces leaf galls on Q. alba (Section Quercus, 
Series Albae) in autumn. 

Distribution. USA: Massachusetts to North Carolina, Michigan, Illinois, Missouri, Arkansas (Burks 1979).

Comments. Fitch (1859) described a similar gall named Cynips Quercus-lana but the adults he reared are 
cynipid inquilines belonging to Synergus according to keys in Cresson (1887) and Lobato-Vila & Pujade-Villar (2021). The galls are indistinguishable from other similar galls, and we cannot determine whether this gall corresponds to Andricus (now Druon) quercusflocci. Dalla Torre & Kieffer (1910: 544) nevertheless considered Andricus quercusflocci to be a possible junior synonym of Andricus quercuslana. The specific name ‘quercuslana’ corresponds to a Synergus species, leaving the gall described by Fitch (1859) as unidentifiable (?Cynips quercuslana Fitch, 1859). 

Druon quercuslanigerum (Ashmead, 1881), comb. nov. 

Cynips q.lanigera Ashmead, 1881: xiii, female, gall. 
Andricus (Andricus) lanigera Ashmead, 1885: 295 [unjustified emendation].
Andricus laniger (Ashmead): Weld, 1951: 634.
Andricus quercuslanigera (Ashmead): Burks, 1979: 1088. 

Gall. Asexual generation galls (Fig 162–163). Creamy white wool-covered gall usually on the underside of the leaf midrib, occasionally also on twigs; whole gall 1.0–7.0 mm in diameter and 2–3 mm high. Pubescence yellows slightly in older galls. Individual hairs making up the wool are straight and 0.5–2.0 mm long. The interior of the gall contains pale brown larval chambers that can be solitary or in groups of 3–6 along the midrib. 

Biology. Alternate asexual and sexual generations are known. The asexual leaf galls (also rarely on twigs) develop in autumn and winter, sexual galls on catkins in spring (Hood et al. 2018); both generations develop on Q. minima and Q. virginiana and asexual galls have also been found on Q. fusiformis, Q. geminata, Q. oleoides (all Section Virentes). 

Distribution. USA: Georgia, Florida, Alabama, Missouri, Louisiana, Texas, and Mexico: Hidalgo. Also introduced with its host plant Q. virginiana in California (Stockton) and Chihuahua (Chihuahua City). 

Druon quercuslanigerum (Ashmead, 1881), comb. nov. 

Cynips q.lanigera Ashmead, 1881: xiii, female, gall. 
Andricus (Andricus) lanigera Ashmead, 1885: 295 [unjustified emendation].
Andricus laniger (Ashmead): Weld, 1951: 634.
Andricus quercuslanigera (Ashmead): Burks, 1979: 1088. 

Gall. Sexual generation galls. Small, on average 1 mm, swelling of the central stem of catkins, with gall shape similar to a grain of rice, or ovate. Surface of gall indistinct from the rest of the central stem of catkin except for swelling (Hood et al. 2018). 

Biology. Alternate asexual and sexual generations are known. The asexual leaf galls (also rarely on twigs) develop in autumn and winter, sexual galls on catkins in spring (Hood et al. 2018); both generations develop on Q. minima and Q. virginiana and asexual galls have also been found on Q. fusiformis, Q. geminata, Q. oleoides (all Section Virentes). 

Distribution. USA: Georgia, Florida, Alabama, Missouri, Louisiana, Texas, and Mexico: Hidalgo. Also introduced with its host plant Q. virginiana in California (Stockton) and Chihuahua (Chihuahua City). 

Druon rusticum Kinsey, 1937, comb. rev.

Druon rusticum Kinsey, 1937: 64, female, gall.
Andricus rusticum (Kinsey): Weld, 1952a.

Gall (Fig. 221). Wool covered, cream-coloured white to tan and russet brown galls; the individual hairs short, straight, hardly covering the larval cells and obviously tufted about each individual cell; making continuous but very irregular, narrowly elongate masses up to 25 mm, average 13 mm long. The larval cells only 1.5 mm long, elongate, 4 to 10 in one cluster.

Biology. Only the asexual generation is known, which induces galls on Q. magnoliifolia (= Q. macrophylla; Section Quercus, Series Leucomexicanae); galls mature in late autumn; adults emerge the following year in April– May (Kinsey 1937). 

Distribution. Southwestern Mexico, Guerrero (Kinsey 1937). 

Druon serretae Pujade-Villar, Cuesta-Porta & Melika, sp. nov.

Gall (Fig. 233). Woolly leaf galls that cannot be distinguished from those of [D. protagion](https://www.gallformers.org/gall/3807), [D. receptum](https://www.gallformers.org/gall/3808) or [D. quercuslanigerum.](https://www.gallformers.org/gall/895)

Biology. Only the asexual generation is known, which induces woolly leaf galls on Q. grisea (Section Quercus, Series Leucomexicanae). Galls mature in October–November; adults emerge from January of the following year, most emerging in March. 

Distribution. Mexico: Aguascalientes. 

Striatoandricus furnessae (Weld, 1913), comb. nov.

Callirhytis furnessae Weld, 1913: 133, gall, female.
Andricus furnessae (Weld): Weld 1922: 16.

Gall. Large woolly mass nearly or completely encircling twigs, 85 mm long by 60 mm in diameter. Each mass is made up of separate larval cells, from a few to over 150. Each cell contains a single larval chamber, and is covered with dense long white wool. Cells are rhomboid, hairy to the base, with thick and woody walls.

Biology. Only an asexual generation is known, inducing galls on Quercus sp.

Distribution. Mexico: Michoacan.

Striatoandricus furnessulus (Weld, 1944), comb. nov. 

Andricus furnessulus Weld, 1944: 12, female, gall

Galls (Fig. 243). A woolly mass partly or entirely encircling small twigs, measuring up to 30 by 25 mm, pure 
white or rosy when young, consisting of a large number of separate biconical cells attached at a common point, each covered with long hairs, about 7 by 5 mm; shorter and broader than in [S. furnessae](https://www.gallformers.org/gall/3791) (Weld 1944).

Biology. Only an asexual generation is known, inducing galls on Q. oblongifolia.

Distribution. USA: Arizona

Striatoandricus guatemalensis (Cameron, 1883), comb. nov.

Cynips guatemalensis Cameron, 1883: 71, gall.
Andricus guatemalensis (Cameron) Ritchie & Shorthouse, 1987: 240.
Synergus dorsalis Cameron, 1972: 72.
Andricus dorsalis (Cameron): Ritchie & Shorthouse, 1987: 240.

Galls. Densely hairy hemispherical masses attached to the midrib of the underside of the leaves. The center is hard and woody, and the fibers radiate from the center towards the edge; the larval chambers are situated along the edge, there being none in the center. Outside the woody central gall is a covering of woolly hairs, white basally, but reddish brown distally. The galls are usually found in pairs, occasionally singly.

Biology. Only an asexual generation is known, inducing galls on Quercus sp. [Quercus peduncularis added as a plausible placeholder]

Distribution. Guatemala: San Jerónimo (Baja Verapaz)

Comments. Cameron (1883) described Cynips guatemalensis based exclusively on gall samples, however the drawings of the galls in the same study were morphologically discordant from his description in the text. This problem has been solved recently by Pujade-Villar et al. (2022). Furthermore, Synergus dorsalis Cameron was described in the same study (Cameron 1883); the type material of which (“Synergus” adult) was examined by Richie & Shorthouse (1987) who concluded that it corresponds to an Andricus. Cameron mentions that S. dorsalis was obtained from the gall of Cynips guatemalensis, therefore S. dorsalis, currently Andricus dorsalis (Cameron), is the inducer of the gall of C. guatemalensis (currently Andricus guatemalensis).

Striatoandricus tenuicornis (Bassett, 1881), comb. nov.

Cynips tenuicornis Bassett, 1881: 92, female, gall.
Diplolepis tenuicornis (Bassett): Weld 1926: 34.
Andricus tenuicornis (Bassett): Weld 1951: 636.

Galls. Densely hairy hemispherical masses attached by a single small point to the upper or under surface of the leaves. They are from 10-20 mm in diameter. The woolly hairs are of a dull russet color and entirely hide the polythalamous gall beneath. The gall interior contains small and extremely thin-walled larval cells. Between them there are a few thin fibrous plates or lamellae separating open spaces. An average size gall contains 14 larval cells (Bassett 1881). 

Biology. Only an asexual generation is only known, inducing galls on Q. arizonica. 

Distribution. USA: Arizona, Mule Pass Mountains (Bassett 1881).

Druon alexandri Melika, Nicholls & Stone, sp. nov.

Gall (Fig. 12). Reddish-yellow furry gall mass (gregarious, multilocular) on underside of leaf, to 20 mm long, projecting from leaf by up to 15 mm. Extremely hard to distinguish externally from the asexual generation galls of D. protagion, D. receptum or Andricus tecturnarum Kinsey, 1920.

Biology. Only the asexual generation is known, which induces furry leaf galls on Q. turbinella (Section Quercus, Series Leucomexicanae). Galls mature in October–November; adults start to emerge in January, peak emergence in in March.

Distribution. USA: Arizona. 

Druon gregori Melika, Nicholls & Stone, sp. nov.

Hosts: Quercus arizonica, oblongifolia

[Photos of the galls appear on page 26]

Gall (Fig. 56). White fluffy gall on the midrib on the underside of leaves, cluster of a few cells. 

Biology. Only the asexual generation is known, which induces woolly leaf galls on Q. arizonica, Q. oblongifolia and Q. rugosa (all Section Quercus, Series Leucomexicanae). Galls mature in October; adults emerged shortly 
afterwards under laboratory conditions.

Distribution. USA: Arizona, Santa Catalina Mtns. and Chiricahua Mtns.

Re-establishment of the Nearctic oak cynipid gall wasp genus Druon Kinsey, 1937 (Hymenoptera: Cynipidae: Cynipini), with description of five new species