The forewing pattern of this species is most similar to that of Macrosaccus morrisella in having the basal strigulae less oblique than those present in Macrosaccus robiniella and Macrosaccus neomexicanus, but it differs from Macrosaccus morrisella in lacking the distinct basal white streak typical of the latter. The male genitalia of Macrosaccus uhlerella are distinct in possessing the most modified, slender valvae (Fig. 28) of any member of Macrosaccus.

(Figs 7, 8). Forewing length 2.2–2.8 mm.

Head: Vestiture of head and antenna similar to Macrosaccus robiniella and Macrosaccus morrisella.

Thorax: Light to dark brown to fuscous dorsally, sometimes with a slight orange luster and a suffusion of fuscous posteriorly; shiny white ventrally; tegula usually orange brown, occasionally with fuscous suffusion posteriorly. Forewing mostly light brownish orange with 4 white costal strigulae, each usually with pale to dark fuscous borders; pattern similar to Macrosaccus morrisella except without a distinct slender, oblique, white streak from tegula at base of wing; 3 white dorsal strigulae usually present, but these oriented less obliquely than in Macrosaccus robiniella; basal strigula white, but sometimes obscure; median strigula connected to second costal strigula to form a narrow white fascia as in 4; dorsal half of wing with black scaling variably present between strigulae; a large black apical spot present similar to that of Macrosaccus robiniella and Macrosaccus morrisella; cilia light grey to white. Hindwing, including fringe, uniformly grey. Legs similar to Macrosaccus robiniella in colour pattern.

Abdomen: Similar to Macrosaccus robiniella, dark fuscous dorsally and white ventrally with greyish suffusion laterally on anterior portion of segments 2–7 and sometimes ventrally on A8.

Male genitalia (Figs 28, 29): Distal half of valva abruptly constricted to ~ 1/3 the width of basal half; saccular lobe broadly produced, truncate. Saccus a long, slender rod ~ 1.3× length of valva. Aedeagus long and slender, ~ 3.0× length of valva, with phallobase only slightly more enlarged than aedeagus.

Female genitalia (Figs 30, 31): Ductus bursae long and slender, slightly longer (~ 1.2×) than length of elongate corpus bursae. Accessory bursae spherical, ~ half the length of corpus bursae, arising from approximately midway along ductus bursae. Corpus bursae elliptical, with series of small, dentate spicules arranged in faint longitudinal folds or striae; walls of anterior end (distal 1/6) of corpus bursae membranous.

Not examined.

(Figs 51–53). The mature mine is an elongate-oval, whitish blotch located on the under (abaxial) side of the leaf usually near the edge of the leaflet. Eventually, as the mine becomes tentiform, the leaf edge is slightly curled (Fig. 51).

(Table 1). Amorpha fruticosa L., (Chambers 1878: 58; Frey and Boll 1878: 276; Walsingham 1889: 119; Braun 1908: 292). Amorpha sp., Robinia sp. (Robinson et al. 2002: 357). The primary host, Amorpha fruticosa, is a shrub up to 4 meters high which occurs naturally from Louisiana to Florida and north to Wisconsin and Pennsylvania. Because no adults reared from Robinia are known or have been examined, the host record reported in Robinson et al. (2002) is questionable.

Argyromiges uhlerella Fitch [type material and deposition not stated, believed lost]: [New York]. Lithocolletis amorphaeella Chambers: Lectotype (present designation), ♀: “Type 1327; Chambers, Colorado; Lithocolletis amorphaeella Cham.; Lectotype ♀, Lithocolletis amorphaeella Chambers, by D. Davis; ♀ genitalia on slide 4530, D.R. Davis”, (MCZ), [head, right wings missing]. Lithocolletis amorphae Frey and Boll: Type material not stated, deposition unknown; [Texas].

UNITED STATES: COLORADO: Specific locality unknown: 1 ♀, lectotype, Lithocolletis amorphaeella Cham., DRD slide 4530, (MCZ). ILLINOIS: McDunnough Co: 3 mi. East of Good Hope, Short Fork Seep, Ti7N-R2W, Section 27–28: 2 ♂, 2 ♀, 7 Aug 2010, emerged 11–17 Aug 2010, leaf mine on Amorpha fruticosa, J. Wiker and T. Harrison, slide USNM 33918, (USNM). Putnam Co: 1 ♂, 1 ♀, 29 Mar 1938, DRD slide 4508; 1 ♂, 18 Aug 1939; 1 ♂, 8 Sep 1940, DRD slide 4507; 2 ♂, 20 Sep 1967, reared from underside leafmine Amorpha fruticosa; 2 ♂, 25 Sep 1940; 1 ♂, 5 Oct 1946, DRD slide 4506, reared from leafmine, Amorpha fruticosa, M. O. Glenn, (INHS). Vermilion Co: Kickapoo State Recreation Area: 1 ♀, 13 Jun 1991, moth iss. 24 Jun 1991, T. Harrison, (INHS). MISSOURI: Boone Co: Colombia: 1 ♀, 14 Dec 1969, W. S. Craig, under bark of sycamore, (USNM). TEXAS: Specific locality unknown: 4 ♀, from Amorpha fruticosa, (BMNH). Dallas Co: Dallas: 2 ♂, 3 ♀, Boll, slide BM 4003, (BMNH); Dallas, Boll. 1876, 1 ♂, 4 ♀, bred from Amorpha fruticosa, Stainton collection 1893-134, (BMNH).

Macrosaccus uhlerella is known to occur from Colorado, Illinois, Missouri, New York, and Texas.

For over 120 years Argyromiges uhlerella Fitch has been regarded as the senior synonym of amorphaeella Chambers. The inadequacy of the original description of Argyromiges uhlerella (quoted below), together with the disappearance of any type material, has caused some uncertainty regarding this insect’s identity. In his review of the insects feeding on Robinia pseudoacacia, Fitch (1859) proposed two names now assigned to Macrosaccus which he believed to be related to the Robinia leafminer: Argyromiges pseudacaciella (now considered a synonymn of Macrosaccus robiniella) and Argyromiges uhlerella. Fitch stated that he did not know the hosts for these two moths (i.e., neither had not been reared). Walsingham (1889) concluded that Fitch’s description of Macrosaccus uhlerella agreed with that of Macrosaccus amorphaeella, proposed 18 years later by Chambers (1877), and he consequently synonymized the latter name. All later workers treating this complex accepted Walsingham’s decision. Closer examination of wing pattern variation within large series of reared Macrosaccus robiniella, however, suggests that Fitch’s description more approximates the greyish forewing colour of some specimens of Macrosaccus robiniella than it does the non-greyish, more brownish forewing colour prevalent in the smaller sample of adult Macrosaccus rearedfrom Amorpha fruticosa examined. Fitch’s description also contains such abnormalities as the “five white spots along their outer sides” and “the tip of the wings is here replaced by a short black stripe thrice as long as it is wide”, both of which may possibly reflect the poor condition of his specimen(s). Worn specimens of Macrosaccus robiniella have been observed with one or two strigulae indistinct or missing, as well as some with reduced apical spots. Similar variation might also be found to occur within moths reared from Amorpha, once more specimens become available for examination.

No type material of “Argyromiges” uhlerella is believed to exist. In 1977, during a search for Fitch’s Lepidoptera types deposited in the USNM, Tim McCabe found a pin bearing Fitch’s label 8158 (the type number for uhlerella) in the main collection. The moth was missing and was presumed destroyed. The pin with that number has since disappeared. Because the name uhlerella has been used consistently as the valid name for this taxon since before 1899, we believe that this usage should continue even though some doubt now exists regarding the correct application of the name.

Argyromiges uhlerella

“337. Uhler’s leaf-miner, Argyromiges Uhlerella, new species.”

“This resembles Pseudacaciella, but is throughout of paler color, the fore wings being golden gray, with five white spots along their outer sides, of which the hindmost ones are small, the others quite large and bordered with blackish upon their anterior sides; and the black dot on the tip of the wings is here replaced by a short black stripe thrice as long as it is wide; whilst the hind wings and their fringes are pale silvery gray. These marks will suffice to distinguish this from the two preceding species.”