270
THE ESSEX NATURALIST
Figure 3. Head of a large male Stag Beetle. Twice natural size.
The first emergences were much earlier (the first specimen was
taken on May 7), but the active season lasted until the first week
of August, as was the case in 1963. Figure 1 shows the capture
dates for the two years. A few were taken in early August in
1963, but exact dates were not recorded. This year a number were
successfully kept in captivity for over seven weeks, the last one
dying on 9th August, four days after the last capture date.
Measurements were again taken and the combined results for
1963 and 1964 are shown in the histograms (figure 2). There was
no significant change in mean size, which was: —
Males Females
1963 49.2 mm 36.4 mm
1964 50.8 mm 36.6 mm
Fewer small males were encountered, but the extremes were lower
(31-63 mm as against 33-65 mm for 1963). Some of the larger
males had excessively developed heads and mandibles. An ex-
ample is shown (figure 3) for comparison with those illustrated in
my previous paper.
A number of breeding sites have been located in Colchester and
it is hoped that further study will enable me to clarify the life-
history, which in various books is said to take three, four or even
five years.
References
Clark, J. T. (1964). The Stag Beetle in North-East Essex. Essex Nat,
31 : 167.
Clark, J. T. (1965). The Stag Beetle. Trans. Suffolk Nat. Soc, 13: 86.
Hall, D. G. (1964). Distribution of the Stag Beetle in Britain. London
Nat, 43: 67.