Locally common in Vermont, but apparently absent in many localities. It may prefer relatively less disturbed habitats. Queens emerge late.
Locally common in the Champlain and Connecticut River Valleys; rare or absent in colder and more heavily forested areas. Colonies die early, often by August.
Locally common in the Champlain Valley; uncommon or rare elsewhere in Vermont. Queens emerge very late.
Rare in Vermont. Hosted by B. fervidus and B. ternarius here; other species elsewhere.
Very rare throughout its range. A parasite of pensylvanicus, and probably in decline in parallel with its host.
An obligate parasite of terricola and affinis; due to their declines, this bee has become a real conservation concern. Possibly extirpated from Vermont.
The most common Psithyrus in Vermont, this one is said to parasitize impatiens, vagans, ternarius, pensylvanicus, bimaculatus, and possibly other bumblebees.
Exceedingly common in Vermont, this species is found in many habitats, including urban areas.
Exceedingly common in Vermont, and present in most locations. Nests said to always be underground. Emerges early, and colonies persist into late October.
Very common in Vermont. Difficult to distinguish from sandersoni. Emerges early, and colonies are relatively long-lived.
Relatively common in many areas of the state. Queens emerge very early, and colonies die early, often by early August.
Uncommon throughout the state, but possibly overlooked due to its resemblance to B. vagans. May prefer forested areas.
Very common in Vermont. Queens of this species emerge very early in spring, usually before any others.
Once very common, and now apparently in decline throughout eastern North America. It seems to be more common in the Champlain and Connecticut River Valleys than in other parts of Vermont.
Once moderately common in the Champlain Valley, but now apparently absent from Vermont and in decline throughout its range. This species nests on the ground in fields, and thus requires unmanaged f... More
Once very common throughout its range, but declined precipitously in the late 1990s. Still missing from much of its former range in eastern NA, but locally common in Vermont. Queens emerge very early.
Formerly common throughout the east, but populations crashed in late 1990’s. Apparently extirpated from Vermont, but a few populations still known from Midwest. Queens emerge very early.