102 
lubricate the skin; it is very tenacious and capable of 
being drawn out into a thread which is used as a means 
of descent from trees and bushes. The most injurious 
species are: (1) The Black Slug (Avion ater, Linn.)- not- 
withstanding its name this species varies greatly in colour 
and may be either black, grey, reddish, or reddish brown. 
When at rest the animal can be further recognised by its 
contracted and almost hemispherical form. (2) The Grey 
Field Slug (Agviolimax agrestis, Linn.) is perhaps the 
most injurious species we have in this country. It is ashy- 
grey in colour with a yellowish or reddish tinge, and occa- 
sionally specimens have a mottled appearance; longitu- 
dinal markings are entirely absent. (3) The Black Striped 
Slug (Limax maximus, L.) 1s the largest of the three and 
may attain a length of over six inches. It is usually some 
shade of grey, with longitudinal markings of a darker 
colour, frequently black. Individuals inclining to brown 
or dull yellow are also not infrequently met with. 
It is well known that both Slugs and Snails confine 
their operations to night, and are seldom evident during 
the day except after rain. It is consequently useless to 
apply remedial measures during the warm parts of the 
day, or in very dry weather, the evening and early morn- 
ing being the most suitable times. The mucous secreted 
by Slugs enables them to resist the action of obnoxious 
substances in the powered condition, they have the faculty 
of crawling out of their mucous investment, and in that 
way léave the powdered material behind them. This 
mucous, however, cannot be secreted indefinitely, and if 
two or more dressings are applied with an interval of 
about fifteen minutes between each application the Slugs 
are usually killed. A mixture of lime and soot applied 
two or three times is an effective remedy, but the lime 
should be quite fresh and very finely powdered. Accord- 
ing to Theobald the most effective substance is hydro- 
oxide of calcium, a I to 2 per cent. solution in water. 
Snails, on the other hand, are more difficult to destroy 
from the fact that they retract themselves into the shell 
and can close the mouth of the latter. In this condition 
they can remain completely dormant for several years. 
Dressings of soot is a well-known remedy against Snails, 
it acts as a deterrent making the plants and surface of 
the soil obnoxious to these animals. Nitrate of soda is 
an effective dressing for use on a large scale against both 
