116 THE ESSEX FIELD CLUB.
smaragdaria), on the Sea-wormwood (Artemisia maritima). About a dozen
caterpillars were found, but all agreed that they required looking for, so well
adapted for concealment is their habit of covering their bodies with fragments of
the food-plant.1 Many "nests" of the young larvae of the "Coast Lackey
Moth" (Bombyx castrensis) were also seen on the Artemisia, and a few other
interesting larvae were noticed, such as Caenonympha pamphilus, Aspilates citraria
(since bred by Mr. Fitch), and Myclois cribrum in the thistle stalks. Among the
plants noticed on the "Saltings," was Suaeda fruticosa (Shrubby Seablite),
decidedly a local species.
The party then walked back to Thorington to catch the 7.3 train to Colchester,
as advertised in a local paper, but to their chagrin the newspaper time-table was
found to be a "delusion and a snare," the only evening train having left an hour
and a half previously. There was nothing to be done but to walk seven miles
along the line into the town, where they arrived weary, dusty, foot-sore and late
for dinner !
Nothing daunted, the "house-party" was up early on Monday morning
perambulating the circuit of the Town Walls under the guidance of the President.
The walls of the ancient Colonia appear to be purely Roman work, and have been
assigned by Dr. Duncan to a date as far back as the second colony in Britain
(about 65 a.d.). They are built of the masses of septaria from the London Clay
of the Essex coast, with alternating courses of Roman tiles, cemented with the
imperishable mortar, the secret of which was so well-known to the Romans, but
which our modern builders strive hopelessly to imitate. The walls as they now
are, stand at an average height of ten feet; their circuit is about 3,100 feet, and
they enclose a space of about 100 acres ; altogether they are the most perfect
remains of the kind in the kingdom, and it is earnestly to be hoped that every
effort will be made to preserve intact such a noble specimen of Roman archi-
tecture."
The main party arrived at Colchester at about 11 a.m., and an assembly was
soon called in the Keep of the Castle, where Dr, Laver acted as conductor, and
pointed out the main features of this most interesting building and gave a sketch
of its history. The Castle stands about the middle of the town, and immediately
within a rampart of earth of irregular pentagonal shape, which is probably of
earlier date than the building itself. The plan of the Keep is similar to that of
the White Tower of London, and most antiquaries now consider the building to
be of Norman age, although much controversy has arisen on this point, some
contending for a Roman origin—an opinion apparently mainly based on the fact
that Roman materials were largely employed in its construction. If the Normans
were the builders it is the largest Keep of that age in England (being double the
size of the White Tower), "with the stern simplicity of its architecture enriched
by the bands of deep red tiles and cream coloured stone in its walls, and internal
1 The majority of these larvae were entrusted to Mr. White's care, but with the exception of
two which were preserved in the larval stage, all died before pupating. On July 21st, Mr. Fitch
bred from his larva, a Moth. At the Meeting of the Entomological Society on June 6th last,
Mr. White exhibited these preserved larvae, and made some remarks concerning the so-called
"case," which the insect is said to construct from portions of its food-plant. This he did not
consider to be really a case, hut he had discovered that the larva possessed on its segments certain
secretory glands, at the apex of each of which there is a bristly hair; this appears to retain pieces
of the plant, which are probably fixed firmly afterwards by means of the secreted fluid. These
pieces are very irregularly distributed, and their purpose is evidently protective. Our readers
will find a sketch of the history of the moth in the Essex Naturalist, vol. i., pp. 120 and 204.
2 See Dr. Duncan's monograph (Trans, Essex Archaeol. Soc, vol. 1); and Duncan's "History
of the Walls of Colchester, 1855," and "Quarterly Review," xcvii (1855) etc.