Our vivarium contains, in addition to the above, two of the three British newts, viz., Lophinus punctatus and L. palmatus. The former, though usually spoken of as the “common newt” is in many districts (as at Haslemere) not so common as the palmate newt. The latter is smaller, and the tail terminates abruptly in a threadlike filament, instead of gradually tapering to a point.
An ants’ nest contained between sheets of glass, on the plan devised by Sir John Lubbock (Lord Avebury) and described in his “Ants, Bees, and Wasps” (p. 2), always proves a source of attraction to visitors in the winter, as well as summer months. We have had for two seasons past a nest of the amber-coloured meadow ant (Formica flava) displayed under these conditions. It is probably the most intelligent of European species, forming the grassy hillocks from 9 to 18 inches high, so commonly seen in some districts. The queen, which is much larger than either workers or males, requires very careful searching for upon opening a nest; but the peculiar little white woodlice (which delights in the long name of Platyarthous hoffmanseggii, they are a sort of guest of the ants) may be always easily discerned.
Every spring we take out of the Museum and arrange in this department a series of our summer migrants, accompanied with general notes on bird migration. The following may be seen now: Swallow, martin, swift, sand martin, cuckoo, corncrake, nightingale, wryneck, nightjar, redstart, yellow wagtail, garden warbler, wheatear, chiffchaff and whinchat.
Kept under a bell glass and fed with lettuce and cabbage leaves are some half a dozen examples of the large edible or vine snail (Helix pomatia), the largest of our native land molluscs. This species occurs chiefly on the chalk in the southern counties. At one time it was supposed to have been introduced by the Romans, but of late years the opinion has gained ground that it was indigenous. In the same quarters is an example of a shell-slug, the Testacella haliotidea, sent from Torquay. The shell-slugs differ from ordinary slugs in having a shell on the tail. They are carnivorous and feed upon earth-worms, which they pursue in their burrows; hence may be considered as gardeners’ friends.
A GILBERT WHITE PAGE.
(Continued from p. 27.)
The curious effect of insect attacks in stimulating the growth of certain parts of the plant which they have damaged may be found illustrated in hundreds of instances. We have just mentioned the pine-apples on the spruce fir, but the currant gall on the male catkin of the oak is yet more striking. In this case a structure which is naturally very shortlived has its vigour enhanced and its life prolonged by the presence of the parasite. In this instance the fly attacks the pollen-bearing flowers and deposits its eggs. These flowers would, in the ordinary course, wither and fall as soon as the pollen has ripened and been blown away. Under the stimulating influence of the larvæ, however, sap is attracted, their stems thicken and become fleshy, and instead of withering, they produce what looks like a handsome bunch of currants.
Another instructive instance of parasitism stimulating growth may be observed at this season in any patch of the common field thistle. Some of the plants are almost sure to be affected by a parasitic fungus. It is present in the stole of the plant, and its influence will cause the affected plants to put forth leaves earlier than the healthy ones. They will also grow faster, and in the course of a month be twice the height of their fellows. The fungus grows in the stem, and finally it will flower out on the surface of the leaves. When this happens the plant will die, but up to that period its growth has been notably vigorous. The fungus is the Puccinia suaveoleus (see Plowright, p. 183.) In some plants it is visible even in early spring, and if abundant will dwarf the plant so affected instead of stimulating its growth.