are more or less common on trees and bushes in Essex, and can be found on elm: P. ulmi, P.
reuteri, P. longipennis, P. tiliae, P. dimidiatus and P. populi.
The predacious shieldbugs Troilus luridus and Pentatoma rufipes are the largest and most
spectacular of the Heteroptera to be found on elm. Both are tree-dwelling species which may
occur on a number of the tree species, and neither are very strongly attached to elm. They are
most likely to be found on elm where it occurs mixed with tall trees of other species.
The tree damselbug Himacerus apterus is a voracious predator which hunts on the foliage
of almost any trees and shrubs growing in fairly sunny situations. It is generally common is
Essex, as elsewhere in the south-east of England, and can often be found on elm at wood margins,
in scrub and along tall broad hedgerows.
A number of species of predacious Heteroptera live on the trunks and branches of trees. No
doubt these species fared better on elm in the days when it regularly formed large trees, but
several of them seem quite happy on the smaller fare now available. The long-legged assassin
bug Empicoris vagabundus is a slow-moving cryptic predator found on a wide range of trees,
and less often on walls or amongst low vegetation. It is rather infrequently recorded, but is
probably widely overlooked. Two members of the family Microphysidae, Loricula elegantula
and L. pselaphiformis are frequent on the trunks and branches of trees in the county. Both
species show strong sexual dimorphism, the short-lived males being fully-winged insects of
delicate appearance, the females short-winged, flightless and much more sturdily built. The
female of L. elegantula is rather brightly coloured, with bright red foreparts contrasting with
the glossy black abdomen. L. pselaphiformis is far less conspicuous in dull brown and black.
L. elegantula is probably the commoner in Essex: L. pselaphiformis may occur more frequently
in shaded situations. Both species are easily overlooked, since both are less than two millimetres
long. Two further species of bark-dwelling bug, Temnostethus gracilis and T. pusillus appear
to be fairly frequent in the county. Both are most frequently found on the trunks of large trees,
and though elm trees may have supported both very frequently in the past it is unusual to record
either from the county's remaining elm.
After its death, elm may continue to support several species of Heteroptera. The barkbug
Aradus depressus usually occurs beneath thick bark on large logs and, particularly, stumps.
Large elm stumps with sufficient bark in the correct state of decay must now be very rare. Two
species of flatbug, Aneurus laevis and A. avenius may be found beneath the bark of thinner
branches. Both are rather local, but are brownish insects, flattened to an improbable degree,
which feed on fungal hyphae. A small black and brown bug, Xylocoris cursitans is an active
predator which lives beneath the bark of dead branches and trunks that has begun to separate
from the underlying wood. It is rather restricted in distribution, being usually, if not invariably,
found in ancient woodland and parkland sites. Within these sites, however, it is completely
catholic in its taste in trees, and will, for example, live beneath the bark of exotic conifers as
happily as beneath that of the English oak.
Where dead elm occurs in such ancient sites, it may support the bug. A relative of X.
cursitans, similar in appearance though darker and more elongate, is Dufouriellus ater. It
appears to be decidedly local, but is probably widely overlooked. It is another predator, and is
found most commonly beneath fairly dry bark on branches and trunks of only a few inches
diameter. Like X. cursitans it is catholic in its choice of trees, but is not restricted by the past
history of a site, and is not even confined to trees. It is sometimes recorded from wholly artificial
circumstances, and one population has been found in the north of England breeding beneath the
iron bands on a barrel used as a table in a pub beer garden.
Auchenorrhyncha
Tapping, or even lightly brushing against, an elm bush or tree in mid to late summer will almost
certainly produce a cloud of pale yellowish insects a few millimetres long. These are leaf
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