FEMALE—Length 10-11 mm.; black; pubescence whitish, rather short on head and thorax, somewhat yellowish on apical leg segments; head somewhat broader than long; eyes very slightly convergent below; clypeus somewhat protuberant, protruding about one-half below suborbital line; cheeks slightly broader than eyes; lateral ocelli somewhat nearer margin of vertex than to eyes; punctures quite deep and distinct on head and dorsum of thorax, fine and densely crowded above antennae but becoming relatively sparse below and on clypeus, minute and obscure on vertex, cheeks becoming finely and obscurely striate, without evident punctures; dorsum of thorax shining between fine, close punctures, these becoming crowded laterally, pleura finely and obscurely rugoso-striate; dorsal area of propodeum finely rugose, poorly defined; wings lightly infuscated basally but becoming quite deeply so apically, veins and stigma pale ferruginous; tegulae piceous, with a narrow, hyaline, anterior rim; hind basitibial plate triangular, acute; legs blackish but apical tarsal segments becoming reddish; abdominal terga minutely and very closely punctate, punctures quite deep and distinct on basal terga, becoming obscure apically, the apical fasciae quite dense, white, subinterrupted on terga 1 and 2.|
MALE—Length 10-11 mm.; black, but with labrum and most of clypeus, tibiae and tarsi yellow, flagella more piceous; length and breadth of head about equal; eyes rather distinctly converging below; clypeus quite strongly protuberant, projecting somewhat more than one-half below suborbital line, somewhat less than half blackened above; mandibles blackish; cheeks somewhat broader than eyes; lateral ocelli slightly nearer margin of vertex than to eyes; basal segment of flagellum considerably shorter than second and following segments, about as broad as long; punctures fine but deep and distinct, very close above antennae, becoming slightly more widely separated below, those on vertex less distinct, cheeks becoming very finely striate below, scutum shining between closely crowded punctures, these becoming somewhat more widely separated posteriorly and on scutellum, pleura very finely rugoso-striate; dorsal area of propodeum finely but rather distinctly rugosostriate; wings subhyaline, becoming lightly infuscated apically, veins and stigma pale ferruginous; tegulae reddened, with an anterior yellow spot; basal leg segments blackened but femora yellowish at tip, tibiae yellowish, but with a reddish or piceous median blotch, tarsi entirely yellow; abdominal terga very finely and closely but quite distinctly punctate, apical margins somewhat reddened, apical fasciae white, dense laterally but becoming thin or interrupted medially, discal pubescence very short and inconspicuous, blackish; sternum 4 very broadly and slightly incurved apically, apical margin of sternum 5 with a broad, subtriangular median emargination, 6 narrowly truncate apically; gonostyli strongly compressed, with a large ventral lobe which is truncate, a finger-like dorsal lobe with a fringe of short setae, a long tuft of curved setae projecting posteriorly and a second tuft of more elongate, curved setae directed toward penis valves, these rather strongly grooved dorsally.
DISTRIBUTION—Holarctic, ranging throughout Canada and the United States, south to Florida; March to September.
FLOWER RECORDS—Althaea, Antennaria, Aronia, Barbarea, Berteroa, Ceanothus, Chrysanthemum, Daucus, Eupatorium, Fagopyrum, Fragaria, Hydrangea, Malus, Melilotus, Oenothera, Oxypolis, Potentilla, Prunus, Ranunculus, Rhus, Ru bus, Rudbeckia, Salix, Solidago, Spiraea, Taraxacum, Trifolium and Vaccinium. Brittain and Newton (1933 and 1934) record rubicundus also on Brassica, Cirsium, Crataegus, Leotodon, Solidago, Tulipa and Veronica. Robertson (1929) records this species (as H. lerouxii) on the following additional genera: Amorpha, Anemonella Antennaria, Anthemis, Arabis, Arctium, Asclepias, Aster, Blephilia, Camassia, Campanula, Capsella, Castalia, Caulophyllum, Collinsia, Comandra, Coreopsis, Crytotaenia, Delphinium, Dentaria, Dianthera, Erigenia, Eryngium, Erythronium, Eulophus, Geranium, Heracleum, Isopyrum, Krigia, Lepachys, Lycopus, Malva, Monarda, Nelumbo, Nepeta, Osmorrhiza, Oxalis, Petalostemon, Polemonium, Polygonum, Psoralea, Ptelea, Pycnanthemum, Rhammus, Ribes, Sassafras, Scrophularia, Silphium, Sium, Smilacina, Stellaria, Symphoricarpus, Teucrium, Thaspium, Tilia, Triosteum, Verbena, Verbesina, Viburnum, Zanthoxylum and Zizia.