Systematic Course. 49 
themselves up into cocoons, which are usually formed of their own hair 
fastened together with a little silk. The cocoons are to be found either 
attached to the leaves or spun up in the litter beneath the trees. Very 
extensive areas of forest in India are sometimes defoliated by these 
insects, with the result, not only of aconsiderable loss of growth, but 
also of injury to the vitality of the trees, which renders them liable to 
the attack of Scolytide and other boring insects. 
Sal forests are specially liable to attack, In 1878 the sAl trees 
throughout two hundred square miles of forest in the Dooars are said to 
have been completely defoliated by caterpillars of the genus Dasychira, 
which may be recognised by the four thick tufts of hair set in the mid- 
dle of the back of the anterior segments of the abdomen. This instance 
may be looked upon as a typical one. The insect mysteriously dis- 
appeared almost as suddenly as it came, owing, it is believed, to the 
attack of the Tachinid parasites (Diptera) to which it is known to be 
very subject. In India Tachine are believed to be about the most im- 
portant agents in keeping down the numbers of defoliating caterpillars 
of this kind, but Chalcididz and probably also Ichneumonide (Hym- 
enoptera) do useful service. In the case of the Nun (Liparis monacha) 
caterpillar, whichhas occasioned an enormous amount of damage to 
spruce inthe forests of Central Europe, besides attacking beech and 
Scotch fir, a disease apparently identical with the fackerze of silk-worras, 
is said to have ultimately proved a most effectual natural remedy, 
though, in the last attack, it appeared too late to prevent injury on a 
vast scale, asthe spruce fir over very large areas died from the des- 
truction of the foliage. The fact is an interesting one, as flachericisa 
disease which attacks both mulberry and Eri silkworms in India. 
The most successful artificial measure adopted in Central Europe 
against the Nun caterpillars seems to have been that of localising the 
attack by forming protecting belts around infested areas, In the Indian 
Forester of July 1891, Sir D. Brandis gives an interesting account both 
of the attack and also of the remedies adopted in different localities. 
Speaking of what was done in 1890 in the “ Diirrenbucher Forst” on 
the banks of the Danube, where the forest was a mixed one, the under- 
growth largely consisting of spruce, he writes : — 
“On the protection belts, which were made 100—130 feet wide, three operation 
were undertaken. First, onall-old stems rings, twelve inches broad, of tar and glue 
were applied at a convenient height, about four feet from the ground. This mixture 
of tar and glue has for some years past been specially prepared, and has, as pre. 
viously mentioned been employed on a large scale against the ravage of the Scotch 
pine moth, the well-known Gastropacha pini.' To make the glue stick on the stems, 
the rough outer bark is scraped off with a sharp knife, which gives a smooth surface 
to the inner reddish tark Hence this operation is commonly designated as rothen, 
to redden the stem. These rings or belts of glue, if the mixture is good, remain 
1 One of the same group of moths with hair-covered defoliating caterpillars.—E. C, C. 
E 
