LOUSE. 
452 
I 
Leewenhoek that the male is furnished at tiie e^t^ 
tremity of tlie abdomen with a sting; and that it 
is this instrument which causes the chief irritation 
suffered from these animals; the suction of the 
proboscis hardly seeming to have caused any per- 
ceptible pain on the skin of his hand. The 
male is readily distinguished from the female* by 
having the tail or tip of the abdomen rounded: in 
the female it is forked or bifid. The same accurate 
observer (Leewenhoek) being desirous of learning 
the proportion and time of the increase of these 
insects, placed two females in a black silk stock- 
ing, which he wore day and night for that purpose. 
He found that in six days one of them had laid 
fifty eggs, and upon dissecting it, he found as many 
more in the ovary: he therefore concluded that in 
twelve days it would have laid an hundred eggs: 
these eggs, hatching in six days, which he found 
to be their natural time, would probably produce 
fifty males, and as many females f; and these 
females, coming to their full growth in eighteen 
days, might each of them be supposed, after twelve 
days more, to lay also an hundred eggs; which in 
six days farther, (the time required to hatch them) 
* It is remarkable that Swammerdam appears to have been 
unacquainted with the diiference between the males and females : 
he even entertained a suspicion that they were hermaphrodites ^ 
gince, on dissecting forty individuals, he found an ovary in them 
all. 
f This is, perhaps, not a very probable supposition ; since it 
appears from the before-mentioned observation of Swammerdam^ 
that the females are far more numerous than tire males. 
