Richmond Green Park, Richmond Hill (N43º53'58.8"W079º23'51.3"elev.195m), York Region, Ontario, Canada
June 18, 2008
Size: 12 mm
This shot shows the acarinarium at the base of tergum 2 of the female Parancistrocerus
specimen (males have it too), here still with a full load of mites that later dispersed. Few other Hymenoptera, such as Xylocopa
(large carpenter bees), have this feature, which carries beneficial 'ninja' mites that may help to keep the nest clear of parasites (see wikipedia
Might make a good glossary term, too?