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

Figs. 253–264

Cynips tenuicornis Bassett, 1881: 92, female, gall.

Diplolepis tenuicornis (Bassett): Weld 1926: 34.

Andricus tenuicornis (Bassett): Weld 1951: 636.

Type examined. Holotype female “Mule Pass Mnts., Arizona ”, E.T. Cox coll.”, “ Bassettia tenuicornis W. B. Bass ”, red label “Paratype No. 52971 USNM ”, handwriting Weld label “ Diplolepis tenuicornis ”.

Additional material examined. Four females, all labelled as “Hopk. US 15639”, “Reared Jan. 23.22”, “ Quercus arizonica ”, “Oracle, Ariz.”, “ L. H.Weld Collector”, Weld’s handwritten label “ Diplolepis tenuicornis (Bass.) det. L. H.Weld”.

Diagnosis. Morphologically most closely resembles S. barriosi (Medianero & Nieves Aldrey, 2019) known from Panama, both having the head and mesosoma dark brown to black, the metasoma reddish brown; the notaulus complete, entirely reticulate pronotum, second metasomal tergum entirely striate, not areolate-reticulate, without smooth dorsolateral area; the mesoscutum longer than broad; mesopleuron entirely and uniformly reticulate, without smooth areas; Rs+M inconspicuous, not reaching basalis, its projection reaching basalis in its lower half (Cuesta-Porta et al. 2020). But in S. barriosi the dorsal part of the mesopleuron is smooth, while in S. tenuicornis the entire mesopleuron is reticulate, except a small part of the speculum which is smooth, shining. Two species, S. sanchezi Pujade-Villar, 2020 and S. georgei (Pujade-Villar, 2011) known from Mexico, differ by having the notaulus incomplete; in S. tenuicornis the notaulus is complete. Also S. nievesaldreyi (Pujade-Villar, 2011) known from Mexico has an entirely sculptured mesopleuron and the second metasomal tergum dorsolaterally smooth, shining, while in S. tenuicornis the entire mesopleuron is reticulate, except a small part of the speculum which is smooth, shining and the second metasomal tergum dorsolaterally striate.

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).