Viktor Sten wrote:

> In 1951 the entomologist N. Tinbergen showed that a wasp Philanthus
> Triangulum (which digs holes in the ground for burying prey insects as food
>
> for its larvae) uses a mental picture of the location of the dug hole, to
> find it on return with prey. If one were to search  on Tinbergen on say
> google.com the said picture is likely to be found.

At the urging of this interesting tip, I did a search, which turned up two of
the original articles by Nicolaas Tinbergen, published in German Journals.
These are:

Tinbergen, N. and W. Kruyt 1938.  Zeitschrift f. Vergleich. Physiol. 25:292.
"Uber die Orientierung des Bienenwolfes (Philanthrus triangularus Fabr.)
III. Die Bevorzugung bestimmter Wegmarken.
and
Tinbergen, N., and W. Kruyt 1938.  Biol. Zentr. 58:425.  "Uber die
Orientierung des Bienenwolfes (Philanthrus triangularus Fabr.)  IV. Heimflug
aus bekannten Gebiet.

Ted Fischer
Dexter, Michigan  USA