Bombus franklini (Frison)
franklini (Frison, 1921:147 [Bremus]) examined
1 name

TAXONOMIC STATUS: This species has been treated as conspecific with B. occidentalis by Milliron (1971), but has since been shown to be very distinct in morphology by Plowright & Stephen (1980) and Williams (1991 [pdf]), in enzyme mobilities by Scholl, Thorp & Obrecht (1992), and in COI barcodes (Williams et al., 2012 [pdf]).

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: W Nearctic Region. B. franklini has one of the narrowest distributions of any bumble bee species world-wide. All recent specimens have been collected within a 60 mile (97 km) radius of Grants Pass, Oregon (Thorp, 1970, 2003, 2005; Thorp et al., 1983). This species has shown dramatic declines in its former range and abundance since 1995 (Thorp, 2003, 2005; Thorp & Shepherd, 2005; IUCN, 2008).

IUCN CONSERVATION STATUS: Preliminary assessment as CRITICALLY ENDANGERED (Williams & Osborne, 2009) by criterion A2 (IUCN, 2001, 2008) that it is inferred to have undergone a >80% population reduction since 1995, that the causes may not be reversible and may not yet have ceased, based on few records of individuals in the last four years. There are suggestions that it may be extinct (Buchmann et al., 2008). The last known record is from 2006 (R. Thorp, in litt.).

Bombus ignitus Smith
ignitus Smith, 1869:207, examined
terminalis Smith, 1873:206, examined, not of Smith in Horne, 1870:193 (= B. festivus Smith)
japonicus Dalla Torre, 1890:139, replacement name for terminalis Smith, 1873:206

DISTRIBUTION: Oriental, Japanese Regions.

Bombus tunicatus Smith
tunicatus Smith, 1852a:43, examined
vallestris Smith, 1878:8
gilgitensis Cockerell, 1905:223, examined
?manaliensis Kumar & Lall, 2004:236

TAXONOMIC STATUS: COI barcodes support the interpretation that the taxon gilgitensis is a dark form of the species B. tunicatus (Williams et al., 2012 [pdf]).

DISTRIBUTION: Oriental Region.

Bombus brachycephalus Handlirsch
brachycephalus Handlirsch, 1888:244
neotropicus (Frison, 1928:151 [Bremus]) examined
krusemani Asperen de Boer, 1990:1

TAXONOMIC STATUS: The description of B. krusemani shows that this nominal taxon, known from a single location, diverges slightly in colour pattern from the otherwise widespread, common and variable Central American species, B. brachycephalus. The information available at present for B. krusemani is consistent with the known range of variation within B. brachycephalus (e.g. Labougle, 1990). Until more evidence to the contrary is available from critical studies of patterns of variation, I shall treat them as parts of a single variable species.

DISTRIBUTION: S Nearctic, N Neotropical Regions.

Bombus coccineus Friese
coccineus Friese, 1903:254, examined

DISTRIBUTION: W Neotropical Region.

Bombus crotchii Cresson
Crotchii Cresson, 1878:184

DISTRIBUTION: W Nearctic Region.

Bombus ecuadorius Meunier
Ecuadorius Meunier, 1890:66
?butteli Friese, 1903:254, examined

DISTRIBUTION: W Neotropical Region.

Bombus fraternus (Smith)
fraternus (Smith, 1854:385 [Apathus]) examined

DISTRIBUTION: E Nearctic Region, W Nearctic border.

Bombus funebris Smith
funebris Smith, 1854:400, examined

DISTRIBUTION: W Neotropical Region, S Neotropical border.

Bombus griseocollis (DeGeer)
grifeo-collis [griseocollis] (DeGeer, 1773:576 [Apis])
separatus Cresson, 1863:165
DISTRIBUTION: W Nearctic, E Nearctic Regions.

Bombus handlirschi Friese
handlirschi Friese, 1903:255, examined
DISTRIBUTION: W Neotropical Region.

Bombus haueri Handlirsch
Haueri Handlirsch, 1888:234

DISTRIBUTION: S Nearctic Region.

Bombus hortulanus Smith
hortulanus Friese, 1904:188, examined
[hortulans Frison, 1925a:155, incorrect subsequent spelling]

TAXONOMIC STATUS: B. robustus and B. hortulanus have been considered both as conspecific (e.g. Franklin, 1913; Frison, 1925a) and as separate species (e.g. Milliron, 1973b; Asperen de Boer, 2007).

B. robustus and B. hortulanus are morphologically similar. Among the specimens I have seen, individuals that have the sides of gastral terga I-II yellow (B. robustus) also have pubescence extending to the middle or almost to the middle of tergum I, and the males have the space between the inner basal process of the gonostylus and the inner apical process narrower than the apical process. Conversely, individuals with the sides of terga I-II black (B. hortulanus) have at least the middle third of tergum I hairless, and the space between the inner processes of the male gonostylus is wider than the breadth of the apical process.

Until more evidence to the contrary is available from critical studies of patterns of variation, I shall treat them as separate species.

DISTRIBUTION: W Neotropical Region.

Bombus macgregori Labougle & Ayala
macgregori Labougle & Ayala, 1985:50, examined
menchuae Asperen de Boer, 1995:47, examined
rasmonti Asperen de Boer, 2007:236, examined
3 names

TAXONOMIC STATUS: B. menchuae was described from a single location and, on the basis of the worker and male I have examined so far, appears to diverge from B. macgregori only in colour pattern. Until more evidence to the contrary is available from critical studies of patterns of variation, I shall treat them as parts of a single variable species.

DISTRIBUTION: S Nearctic Region.

Bombus melaleucus Handlirsch
melaleucus Handlirsch, 1888:228, examined
volucelloides Gribodo, 1892:119
melanoleucus Schulz, 1906:267, unjustified emendation

TAXONOMIC STATUS: Several of these nominal taxa have been treated as separate species.

B. volucelloides is closely similar to B. melaleucus, but has been considered to be a separate species (e.g. Milliron, 1973b; Asperen de Boer, 2007). B. vogti is also similar to B. volucelloides, and these two taxa have been considered both as conspecific (e.g. Franklin, 1913; Labougle, 1990) and as separate species (e.g. Milliron, 1973b; Asperen de Boer, 2007).

There is very little material available of the males in this group from South America, but the males of B. vogti are distinctly different in the morphology of the genitalia. B. nigrothoracicus seems more likely to be conspecific with B. vogti than with B. ecuadorius (see the comments on B. ecuadorius).

Thus B. melaleucus is interpreted here in a broad sense, to include much variation that is not yet well understood. While awaiting more evidence from critical studies of patterns of variation, I treat them initially as parts of a single variable species.

NOMENCLATURE: For this species, the oldest available name of which I am aware is B. melaleucus, which becomes the valid name. The name B. volucelloides has been in most common use for just part of this species. However, it seems premature to conserve B. volucelloides by suppressing B. melaleucus until the taxa are better understood, because the name B. melaleucus might yet be required for a separate species.

DISTRIBUTION: N Neotropical, W Neotropical Regions.