Lasioglossum (Dialictus) eophilus ( Ellis, 1914 ),

Gardner, Joel & Gibbs, Jason, 2020, The ‘ red-tailed’ Lasioglossum (Dialictus) (Hymenoptera: Halictidae) of the western Nearctic, European Journal of Taxonomy 725, pp. 1-242: 78-81

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Lasioglossum (Dialictus) eophilus ( Ellis, 1914 )


Lasioglossum (Dialictus) eophilus ( Ellis, 1914) 

Figs 36–37View FigView Fig, 103AView Fig, 108AView Fig, 109BView Fig

Halictus eophilus Ellis, 1914a: 153  (holotype, ♀, deposited in CAS, examined).

Halictus (Chloralictus) eophilus  – Sandhouse 1924: 3 (key).

Lasioglossum (Chloralictus) eophilium  – Michener 1951: 1113 (catalog, lapsus calami).

Dialictus eophilius  – Hurd 1979: 1966 (catalog, lapsus calami).

Dialictus eophilus  – Moure & Hurd 1987: 100 (catalog).


Females of Lasioglossum eophilus  can be recognized by the mesepisternum very coarsely sculptured and mostly rugose, ocelli slightly enlarged (separated by ~0.5 OD), metapostnotal rugae strong and reaching the posterior margin, T1 with wedge-shaped median impunctate area, and metasoma mostly brown, only sometimes becoming orange on the sterna and rims of the terga. They are most similar to L. miltolepoides  sp. nov. and L. lilianae  sp. nov. Females of L. miltolepoides  sp. nov. have the acarinarial fan absent, ocelli normal (separated by ~0.8 OD), mesepisternum often rugulose but not strongly rugose, and metasomal terga with less extensive tomentum. Females of L. lilianae  sp. nov. have the mesepisternum shiny and distinctly (although densely) punctate, tomentum more extensive (especially on the mesosoma), and clypeus apical margin and metasoma usually red-orange.


Ellis (1914a) named this species by Latinizing the Greek noun ‘ eos ’ (‘dawn’) and the word ‘ philos ’. ‘ Philos ’ can be interpreted as either a noun (‘friend’) or an adjective (‘loving’, ‘beloved’). According to Article 31.2.2 of the International Code of Zoological Nomenclature ( International Commission of Zoological Nomenclature 1999), if the original author does not specify the intended grammar of an ambiguous name ( Ellis 1914a did not), it is treated as a noun by default. The specific epithet is therefore not declinable and should remain eophilus  .

Material examined


UNITED STATES – New Mexico • ♀; La Cueva , Organ Mountains ; [32.32° N, 106.61° W]; 1615 m a.s.l.; 5 Sep. year unknown; Townsend leg.; ex Datura inoxia  ; CAS 15604View Materials.GoogleMaps 

Other material

MEXICO – Sonora • 1♀; Rancho San Bernardino , Cafe Transect 1, Elia Thesis Study ; [31.32° N, 109.26° W]; 1 Aug. 2001; RLMGoogleMaps  1♀; Rancho San Bernardino , Cafe Transect 5, Elia Thesis Study ; [31.32° N, 109.26° W]; 3 Aug. 2001; RLMGoogleMaps  2♀♀; Rancho San Bernardino , quarry , gravel pit; 31.31964° N, 109.26926° W; 18 Aug. 2003; RLMGoogleMaps 

UNITED STATES – Arizona • 1♀; Cochise Co., San Bernardino NWR , Bosque dry, Site 8, Transect 2; 31.33735° N, 109.231° W; 15 Oct. 2002; RLMGoogleMaps  1 ♀; Cochise Co., San Bernardino NWR , Grassland , Site 5, Transect 3; 31.33861° N, 109.25306° W; 18 Sep. 2001; RLMGoogleMaps  1 ♀; Cochise Co., San Bernardino NWR , Shrub , Site 1, Transect 4; 31.33423° N, 109.23325° W; 22 Jul. 2007; RLMGoogleMaps  . – New Mexico • 1 ♀; Socorro Co., Sevilleta NWR ; [34.3° N, 106.8° W]; 17 Jun.–1 Jul. 2003; K. Wetherill leg.; PCYUGoogleMaps  1 ♀; same location as for preceding; 26 Jul. 2001; K. Wetherill leg.; PCYUGoogleMaps  .



COLOURATION. Head and mesosoma blue-green; clypeus apical colour black to reddish brown; labrum reddish brown to orange; mandible orange with black base and red tip; flagellum black to reddish brown dorsally, reddish brown to orange ventrally; pronotal lobe reddish brown to orange; metasoma reddish brown to orange with discs of terga sometimes black, rims of terga and sterna broadly translucent yellow, and dark spiracular spots on T3–4; legs reddish brown with femur-tibia joints, base and apex of tibiae, and tarsi reddish brown to orange; tegula orange; wing membrane hyaline, veins with subcosta dark brown, otherwise orange.

PUBESCENCE. Body hair colour white. Tomentum dense on gena, pronotal collar and lobe, space between pronotal lobe and tegula, T2 basolaterally, and T3–4 throughout; sparse on face below eye emargination and metepisternum. Scutum hair thin. Wing hairs dark or light, short and dense. Acarinarial fan complete, sparse. T2 fringes sparse, T3 fringes sparse.

SURFACE SCULPTURE. Clypeus punctures moderately dense in basal half (i= 1–2 pd), large and irregularly sparse apically (i <3 pd), sculpture shiny, sometimes weakly imbricate basally; supraclypeal area punctures moderately dense (i=1–2 pd), sculpture shiny; paraocular area punctures crowded (i=0 pd), sculpture shiny, becoming weakly imbricate around antenna socket; frons punctures crowded (i=0 pd), sculpture shiny to imbricate; vertex punctures dense laterally (i ≤ 1 pd), sparse medially (i=1–3 pd), sculpture shiny, sometimes imbricate laterally; gena punctures moderately dense (i=1–2 pd), sculpture shiny, sometimes becoming weakly lineate posteriorly and ventrally; postgena sculpture shiny, becoming tessellate and weakly lineate posteriorly and laterad of hypostomal carina; tegula punctures absent; scutum punctures dense (i <1 pd), slightly sparser submedially (i ≤ 1 pd), sculpture shiny, becoming tessellate anteromedially; scutellum punctures dense marginally and on median line (i ≤ 1 pd), slightly sparser submedially (i= 1–2 pd), sculpture shiny, sometimes tessellate marginally; metanotum sculpture finely ruguloso-punctate; metapostnotum rugae strong, anastomosing, reaching margin, sculpture shiny to weakly tessellate; preëpisternum sculpture areolate-rugose; hypoepimeron punctures absent, sculpture finely areolate-rugose; mesepisternum punctures dense (i ≤ 1 pd), becoming crowded (i=0 pd) and indistinct dorsally, sculpture areolate-rugose dorsally, becoming smooth and shiny or imbricate ventrally; metepisternum sculpture lineate dorsally, finely areolate-rugose medially, imbricate ventrally; propodeum lateral face sculpture rugulose anteriorly, tessellate posteriorly; propodeum posterior face sculpture tessellate with weak vertical striae; T1 anterior face sculpture shiny; T1 dorsal surface punctures moderately dense (i= 1–2 pd), becoming fine and sparse medially (i=2–6 pd), impunctate in large apicolateral oval patches and median wedge, sculpture shiny; T2 disc punctures moderately sparse (i =1–2 pd), becoming finer and sparser medially (i=2–4 pd), disc sculpture shiny, rim punctures moderately dense (i=1–2 pd), sometimes obscure, rim sculpture shiny to weakly coriarious.

STRUCTURE. Face length/width ratio 0.84. Clypeus projecting ~50% below suborbital tangent; clypeal area length/width ratio 0.47; apicolateral denticles rounded knobs; supraclypeal area length/width ratio 0.89. Ocelli separated by about 0.5 OD. Forewing with 3 submarginal cells; pronotal angle obtuse; tegula shape normal. Intertegular distance 1.03 mm. Scutum length/width ratio 0.76; scutum/scutellum length ratio 2.35; scutellum/metanotum length ratio 1.74; metanotum/metapostnotum length ratio 0.64. Propodeum lateral carinae not reaching dorsal margin; oblique carina absent. T2 depressed apical rim length less than 50% of segment. (n=1)




Southern Arizona, New Mexico, and northern Sonora ( Fig. 37View Fig).

Floral records

ASTERACEAE Giseke  : Helianthus  (MH87) • FABACEAE Juss.  Dalea  : D. lanata Spreng. D. L. var. terminalis (M.E. Jones) Barneby  (MH87) • Psorothamnus  : P. scoparius (A.Gray) Rydb.  (MH87) • LOASACEAE Juss.  Mentzelia  L. M. multiflora (Nutt.) A.Gray  (MH87) • SOLANACEAE Adans.  Datura  L. D. inoxia Mill. 

DNA barcodes

Two sequences available (BOLD process IDs: DLII1271-08, DLII1272-08; BIN: BOLD:AAF3976). Lasioglossum eophilus  differs from all other western red-tailed L. ( Dialictus  ) by 1 fixed substitution: 102(C) (Supplementary file 4).


Rare. Ellis (1914a) reports that the type specimen was collected before sunrise, and notes the relatively large ocelli. Lasioglossum eophilus  may be specialized for matinal activity; additional early morning collecting may reveal it to be more common than current records indicate.
















Lasioglossum (Dialictus) eophilus ( Ellis, 1914 )

Gardner, Joel & Gibbs, Jason 2020

Dialictus eophilus

Moure J. S. & Hurd P. D. 1987: 100

Dialictus eophilius

Hurd P. D. 1979: 1966

Lasioglossum (Chloralictus) eophilium

Michener C. D. 1951: 1113

Halictus (Chloralictus) eophilus

Sandhouse G. A. 1924: 3

Halictus eophilus

Ellis M. D. 1914: 153