Key points are not available for this paper at this time.
Queens of Bombus terrestris, B. hypnorum, B. lucorum, B. hortorum, B. lapidarius and Psithyrus sp., infected with the parasitic nematode, Sphaerularia bombi, were collected and studied in the Netherlands from April to September, 1971. In June, the infected queens gathered in a special wooded area which partially overlapped with a normal hibernation site. These queens were observed digging in the soil and depositing third-stage juvenile nematodes through their anus. The nematodes entered the soil and molted to the adult stage in approximately 2 months. Mating occurred and the infective females were ready to penetrate a new host. Two molts occurred in the egg of S. bombi and the nematodes matured to third-stage juveniles in the host. The free-living stages of S. bombi are re-described with special emphasis on the pharyngeal region.
Poinar et al. (Sat,) studied this question.