B. vosnesenskii
A common early-summer species, most of B. vosnesenskii's nests will be in the ground in an old mole or mouse nest. We have been raising bumblebee species native to the west coast for use in pollination. This nest is one that was raised. This species can have large nests with as many as 400 workers.
In this picture of a B. vosnesenskii nest you can see all the stages of the developing brood. At the top center you can see 6 brown egg pods. You can see 4 more of the egg pods on the board. The eggs hatch into larvae and grow in a larvae pod. You can see 4 larvae pods on the right side (comma shape). The left side shows the larvae separating from the pod. The larvae spin a cocoon (pupa cell) that they pupate within and hatch from as an adult