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the way, followed for some two feet by single caterpillars in Indian 
file, then came ranks in twos, succeeded, at about the same distance, 
by threes, fours, fives, &c., until the main body advanced twenty 
abreast, in so orderly and compact a manner that no human army 
could move with greater regularity or be more obedient to the word of 
command. As soon as the leading caterpillar stopped, the whole 
army halted ; when he advanced, they advanced, until a fresh pastur- 
age had been found, then they all dispersed, until some signal called 
them all together again. 
Woe betide the luckless individual who approached them while 
on the march, or incautiously handled them, for the tufts of short 
hairs, with which they were covered, possessed the power of producing 
an inflammatory irritation, worse even than the sting of a nettle. It 
is reported that in some cases, where persons have been stung 
severely, serious and sometimes fatal illnesses have resulted. 
Not only when living, but even when dead, the hairs of this cater- 
pillar possessed the same urticating properties. Thus Reamur, who 
had written a monograph on this moth, stated that he suffered, after 
handling the dead caterpillar, for days with an itching, in consequence 
of some of the short stiff hairs sticking in his skin, and being, at first, 
ignorant of the cause, and rubbing his eyes with his hands he brought 
on such a swelling of the eyelids that he could scarcely open them. 
Bonnet, too, who lifted some of these caterpillars from water in which 
they had been drowned, felt a numbness of the fingers, followed by an 
itching and burning sensation. 
Fortunately or unfortunately, he had not come across this cater- 
pillar, which abounded in France, and in 1865 was the cause of so 
much annoyance to promenaders in the neigbourhood of Paris that 
parts of the Bois de Boulogne were closed to prevent discomfort to 
those who incautiously approached the trees, where the larvae were, so 
that he only knew the hairs from published drawings of them, 
We had in this country several caterpillars, whose hairs produced 
the same or similar effects with some people, and as these hairs 
presented, microscopically, diversity of form he would specially direct 
attention to them. Among the most notable were L. guercifolia, the 
lappet ; O. Pofatoria, the drinker ; B. neustria, the lackey ; B. guer- 
cus, oak eggar ; EZ. danestris, small eggar ; O. pudibunda, hop dog ; 
O. antigua, vapourer ; L. dispar, the gipsy ; ZL. salicis, the satin; 
L 
