34 THE INSECT WORLD. 
by four fine hairs, fixed to one another, and seated in its interior. 
It is by means of this complicated apparatus that the louse pricks 
and sucks the skin of the head. The thorax is nearly 
square, and divided into three parts by deep incisions. 
; The abdomen, strongly lobed at the sides, is composed 
i,’ of eight rings, and is provided with sixteen spiracles. 
The limbs consist of a trochanter, a thigh, a shank, 
and a tarsus of a single joint, and are very thick. 
eae A strong nail, which folds back on an indented projec- 
tis) magnised. tion, thus forming a pincer, terminates the tarsus. It 
is with this pincer that the louse fastens itself to the hair. 
Lice are oviparous. Their eggs, which remain sticking to the 
hair, are long and white, and are commonly called “nits.” The 
young are hatched in the course of five or six days; and in 
eighteen days are able to reproduce their kind. Leuwenhoek 
calculated that in two months two female lice could produce ten 
thousand! Other naturalists have asserted that the second gene- 
ration of a single individual can amount to two thousand five 
hundred, and the third, to a hundred and twenty-five thousand ! 
Happily for the victims of these disgusting parasites, their repro- 
duction is not generally to this prodigious extent. 
Many means are employed to kill lice. Lotions of the smaller 
centaury or of stavesacre, and pomatum mixed with mercurial 
ointment, are very efficacious. But the surest and easiest remedy 
is to put plenty of oil on the head. The oil kills the lice by 
obstructing their trachez, and thus stopping respiration. 
There are other kinds of lice, but we will only mention the 
louse which infests beggars and people of unclean habits. Pedi- 
culus humanus corporis, producing the complaint called phthiriasis. 
In the victims of this disease these parasites increase with fearful 
rapidity. This dreadful disorder is often mentioned by the 
ancients. King Antiochus, the philosopher Pherecydes of Scyros, 
the contemporary and friend of Thales, the dictator Sylla, 
Agrippa, and Valerius Maximus are said to have been attacked 
by phthiriasis, and even to have died of it. Amatus Lusitanus, 
a Portuguese doctor of the sixteenth century, relates that lice 
increased so quickly and to such an extent on a rich nobleman 
attacked with phthiriasis, that the whole duty of two of his ser- 

