LIPARIS MONACHA. 317 



ichneumon wasps. Finally, towards the end of the last 

 great swarm of the Nun moth in Bavaria, 1890, fungi, 

 especially bacteria, were destroying the caterpillars, the latter 

 became sleepy, and hung bent like horseshoes on the twigs, or 

 in masses at the tops of the trees. If such caterpillars are 

 squeezed, a brown stinking liquid exudes, whilst healthy 

 caterpillars exude green liquid. 



e. Remedial Measures. 



i. Collection, and destruction of the eggs by fire, from autumn 

 till the middle of April. The piece of bark on which the eggs 

 are laid is removed, and the eggs scraped off with a knife into 

 a bag furnished with a wooden funnel-shaped mouth. The 

 stems are cleared up to 16 feet high, preferably by day- 

 labourers, at first on foot and then with a ladder, and the 

 woods in which many moths have been observed should be 

 first treated. This treatment is easier in smooth-barked pole- 

 woods of spruce than in older woods with rough bark. 



One gramme-weight of eggs contains about 1,200, and the 

 cost of collection is about 3rf. to Is. for 15 grms. In the winter 

 of 1839-40, in the Biesenthal forests near Eberswald, 10 tons 

 of eggs were collected. The eggs should be burned in small 

 lots, as otherwise they explode like gunpowder. 



ii. Killing the clusters of newly-hatched caterpillars in April 

 and May by means of cloths, brushes, or by rubbing them 

 with moss, sods, etc. Great care must be taken to seize the 

 proper moment for this operation, and a delay of only a few 

 days may prevent its being done. The cloths, etc., used may 

 be soaked in tar to render their action more efficacious. This 

 operation is also best done by daily labour, but under careful 

 supervision, one overseer being appointed for every 20 to 30 

 workmen. One man should be able to work over 6 to 8 acres 

 per diem, and the most suitable place to work in is among 

 young poles, where the caterpillars can be readily seen, and 

 are not too high up the stems. 



iii. Collection of caterpillars and pupae, commencing in June. 

 Small caterpillars are usually collected in young growth, on to 

 which they have been blown ; later on, when they have ceased 



