170 THE ESSEX NATURALIST.
leaves, and in maturity scale-like addressed leaves. So different
are the two types that for a number of years the juvenile foliage
was thought to belong to a different genus and was given the
name of Retinospora ; cuttings taken from this stage never
assume the mature type of foliage.
The junipers form the last genus, Juniperus, we have to con-
sider. The fleshy berry-like fruit is formed by the union of
bracts, which are at first free. Our English Juniper, J. communis,
is seldom grown, but the Chinese species, J. Chinensis, is often
cultivated and forms a bush or small tree. Both the juvenile
and adult types of foliage are seen on the same plant, the former
towards the base where the light is dim, and the closer scale
leaves at the ends of the shoots where exposed to strong light.
The male plants are more compact and pyramidal than the female.
I have attempted to give in this sketch merely the most strik-
ing characters that distinguish the genera and species from each
other. I have not touched on the subject of the more intimate
structure of the leaves, the stem and the cones, all of which seem
to call for attention. But should anyone feel drawn to making
even a cursory study of conifers. I can assure them from my
own experience that it is one of ever-increasing interest.
ON INSECTS SUCKING THE SAP OF TREES.
By CHARLES NICHOLSON, F.E S,
(Read 29th November, 1919.)
ON the occasion of the Club's meeting on 30th Nov., 1918,
when Mr. Miller Christy read some notes on the above
subject—subsequently printed in this volume (pp. 10-12)—I
expressed a wish to inspect the tree to which his notes referred,
and, at his invitation, I paid a visit to his garden at Chignal
St. James, on the 23rd August, 1919.
The day was dull and not over warm, but occasionally bright-
ened with short bursts of sunshine. On arriving at the tree
in the afternoon, I found a good number of wasps scattered up
and down the main trunk of the tree, from near the ground to
a height of at least 50 or 60 ft., and also along a long limb, which
extended almost horizontally towards the S.E. Most of the
wasps (all of which appeared to be workers of Vespa germanica),