THE ENTOMOLOGICAL EVIDENCE

The primary task was to investigate and explain the source of blockage in an elbow (B2) and in other parts of the fuel supply unit recovered from the wreckage of a private airplane. A small clump of pollen asso ciated with a disc-shaped gummy mass of plant fibers suggested that be es belonging to the family Megachilidae might have been responsible fo r accumulating these plant materials. Examination of other parts of th e fuel control unit revealed three dead adult bees identified as Osmia gaudiosa Cockerell (Megachilidae) and a single dead individual of the genus Ashmeadiella (Megachilidae). A survey of the tubing of a heater that had been stored showed that 69% of its tubings and fittings cont ained nest material and other arthropod debris including those of Ashm eadiella meliloti (Cockerell) and Anthidium sp. (Megachilidae). Throug h SEM examination, a single branched hair partly embedded in the clump of pollen was matched with the postgenal hairs of an adult Ashmeadiel la. These facts left no doubt that the B2 elbow mass was part of a nes t of Ashmeadiella. This conclusion was consistent with the facts that the wreckage had been available to the bees for nesting during the ent ire time of the spring and summer nesting season, and that the plant m aterials (leaves of Sphaeralcea and pollen sources) were readily avail able near the storage yard during that time. Contamination of the wrec kage by nesting bees was obviously a post-crash phenomenon. Plant mate rials as well as dead bees would have been consumed by the intense fir e that accompanied the crash if they had been present before.