84 CERTAIN PARASITIC INSECTS. 
interest to the botanist, and many of them are eagerly sought 
as the choicest ornaments of our conservatories. Not so with 
their zoological confreres. All that is repulsive and uncanny 
is associated with them, and those who study them, though 
perhaps among the keenest intellects and most industrious 
observers, speak of them without the limits of their own 
circle in subdued whispers or under a protest, and their 
works fall under the eyes of the scantiest few. But the 
study of animal parasites has opened up new fields of re- 
search, all bearing most intimately on those two questions 
that ever incite the naturalist to the most laborious and 
untiring diligence — what is life and its origin? The sub- 
jects of the alternation of generations, or parthenogenesis, 
of embryology and biology, owe their great advance, in large 
degree, to the study of such animals as are parasitic, and the 
question whether the origin of species be due to creation 
by the action of secondary laws or not, will be largely met 
and answered by the study of the varied metamorphoses and 
modes of growth, the peculiar modification of organs that 
adapt them to their strange modes of life, and the conse- 
quent variation in specifie characters so remarkably charac- 
teristic of those animals living parasitically upon others.* 
With these considerations in view surely a serious, thought- 
ful, and thorough study of the louse, in all its varieties and 
species, is neither belittling nor degrading, nor a waste of 
time. We venture to say, moreover, that more light will be 
thrown on the classification and morphology of insects by the 
study of the parasitic species, and other degraded, wingless 
forms that do not always live parasitically, especially of their 
embryology and changes after leaving the egg, than by years 
of study of the more highly developed insects alone. Among 
Hymenoptera the study of the minute Ichneumons, such as 
the Proctotrupids and Chalcids, especially the egg-parasites; 
* Wi 1 Ta dhat 
Ye notice f Parasitology has for some- 
time been issued in Germany--that favored land : of du. It is the * Zeitschrift 
für Parasitenkunde," edited by Dr. E. Hallier and A , Jena. 
