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THE DIGGER WASP
M E T H O D OF C O N V E Y I N G AND STORING THE PREY
The hunting grounds were trunks of trees, logs and the foliage of eiders and brambles. The prey consisted of two-winged flies which were more or less paralysed before conveyance to the nest. Sometimes prey taken from them were able to move their legs, and on one occasion when the fly was released it was capable of running and Aying erratically for periods of some seconds duration. The wasp carried its prey the right way up, both in flight and when moving over a surface, by embracing it with its middle legs between the heacl and thorax. The fly appeared as if attached to a swivel which allowed it to respond when carried over a rough surface. The flies were packed tightly in the cells with their heads pointing away from the entrance. Where more than one wasp was using a main burrow, all returned after an absence of about 20 minutes, following each other with their prey at intervals of two or three minutes. Seidom would one be seen to leave before all had returned. Occasionally after depositing the prey one would loiter at the entrance while three or four passed in and out, the outgoing wasp allowing the incoming one, with or without prey, a free passage by squeezing against the side of the burrow.
HOMING
The homing instinct of this wasp was fairly accurate. It appeared to have a habit of alighting some distance from the nest hole, sometimes only a few inches, occasionally a yard or more especially where nettles and the branches of eider shrubs were overhanging the nest holes. Some alighted with their prey on the foliage of these. After a short rest they would leave, but appeared to have lost their sense of direction, and again returned to the foliage, repeating this once or twice before alighting three or four inches away from the nest hole, and then approaching it as if uncertain of its position. After resting upon the foliage, the wasp appeared to have some difficulty in adjusting its prey for further flight, but at no time did it release the fly from its grasp.
THE
LARVA, P U P A A N D
COCOON
T h e following is a description of an almost mature larva : length 12 mm., legless and glossy, head translucent light brown ; mandibles black. Ist Segment translucent white, 2nd to lOth translucent bluish-white ; 1 Ith (anal) segment translucent white. Extending along the dorsum from the 2nd to the lOth segment were two dark bluish subcutaneous lines 2 mm. apart, the colour