526 THE SOCIAL LIFE OF THE LOWER ANIMALS. 
maintaining life. A large number of them are as well provided 
as others with organs for working, and only seek aid at certain 
periods in their lives. There is not, as has been thought, a spe 
cial class of parasites, but all classes of lower animals contain 
them. We may divide them into different categories ; in the first 
we may reunite all those which are free at the beginning of life, 
swimming about and taking their sport without seeking aid of any 
one, until the infirmities of age oblige them to seek refuge. Cov- 
ered with the toga pretexta they live at first like true Bohemians — 
and take their rest in some good inn.* Sometimes it is both the 
males and females which seek this kind of aid at the coming 
on of old age;7 at other times it is the females alone, while the — 
male continues his vagabond life.t It happens also that the female 
drags along her spouse, and maintains him completely during his i 
captivity ; the male remains a small boy in size as well as habits, 
and if the host who feeds her, serves him with liquor, she in pe 
turn affords her husband food.§ Few females of the Lernæans ; 
can be found which do not carry about with them their liliputian 
males, who do not quit their wives any more than their own Saai : 
ows. All the parasitic crustacea take their place in this first 
category. 7 
We also find some— those hobgoblins of ichneumons for eX 
ample— which are perfectly free in their adult age, but call for 
support in their youth. There are numbers of these insects, which 
on leaving the egg are literally put to nurse; but the day er 
they throw off their larval robes, they know no pae | 
armed from head to foot, they bravely seek adventures like a 
insects.|| In this category are found the parasitic dipterous #7 
hymenopterous insects. oe 
There are also some which are classified from their mode of 7 
all changing their hotel, not to say establishment, gener 
their age and constitution. From the time they leave he ae 
they solicit favors, and all their journey is vigorously mi er e 
in advance. We happily know to-day the steps in this J? y 
the cestode and trematode worms. These flat and s 
begin life in a sort of vagabondage, provided with a ciliat ‘ 
a mo the Lernæans, the ticks, etc. 
$ The Pilaria medinensis, or guinea worm, and several other 
The Lernæans in general. 
|| The Ichnenmons and Œstrus among insects. 
