THE STAG BEETLE IN NORTH-EAST ESSEX 171
simply had a small piece of the wing case clipped, on the right
for those released at C.R.G.S. and on the left for those released at
Shrub End. We were disappointed to find that the Stag Beetle
apparently does not travel any great distance in spite of its fairly
strong flight. Only two individuals were recaptured more than a
hundred yards from the point of release. One travelled from the
School to Lexden Church, and the other from Shrub End to
Cambridge Road—both distances of about one mile. However,
one marked individual was reported from Witham, a distance of
nearly twelve miles from the release point. Unfortunately the
insect was not captured, and the markings as described by the
boy who saw it did not correspond with any of those on record.
There are therefore two possibilities—that the marking was in-
accurately observed and that one insect did cover twelve miles;
or that there was another club in the Witham district also survey-
ing these insects unknown to us.
One of the best known features of the Stag Beetle is its
variation in size. All insects vary somewhat in size, but since
there is little if any growth after the emergence of the mature
insect it is usually possible to give a particular size as the normal
one for most insects. A large male of the Stag Beetle will be more
than twice the dimensions of a small male, and therefore some
eight times its weight. On the whole the male is the longer sex,
although there is a considerable overlap in size. Nevertheless
there is less disparity in weight, as the female is the more massive
of the two. Measurements during the survey were taken primarily
to confirm the identity of recaptured specimens. The length was
taken as the distance from the tip of the mandibles ("antlers") to
the end of the abdomen. The resulting size distribution is shown
in the accompanying histograms (figure 3). There is much greater
size variation in the male than in the female. This is due to the
Figure 4. Extremes of form in the heads of male Stag Beetles. Twice
natural size.