PARASITES OF SPIDERS AND THEIR EGGS. 61 
then encompassed with a maze of closely intercrossed lines, which to the 
human judgment seems impenetrable by the mother hymenopter. Yet this 
cocoon is among those most frequently parasitized. 
Of course, one is always at liberty to offer as explanation the suggestion 
that this very exposure to attack has, in the struggle for survival, produced 
the evolution of the more perfectly armored cocoons. In short, 
Effect of there has been a conflict between the mother aranead and the 
ble aklig mother hymenopter, something like that between defensive plate 
vival, armor on battle ships and offensive projectiles. The difficulty 
with such an explanation is to establish a point of contact be- 
tween mother, offspring, and the facts of life from which to postulate con- 
ceivable interaction and reaction. The theory craves an available pou sto. 
The danger, if apprehended at all, would only be discerned by the eggs, 
which are the objects attacked ; moreover, the impression must be conveyed 
through those eggs within the parasitized cocoon which were fortunate 
enough to escape destruction. To suppose that the reactionary influence of 
environment could thus operate through a sensitive egg to a conscious 
spiderling, and so to the maternal instinct of the adult female, and thus 
on by heredity, through infinitesimal increments of the protective wards 
and armor of a silk enswathed or mud daub cocoon, lays a rather heavy 
burden upon the scientific imagination, even in this heyday age of evolu- 
tionism., The possibility of cocoon evolution by transmittal through the 
adult mother need not be considered; for in the ease of the above named 
species, and most others upon the list, the mother is necessarily eliminated 
from the problem. In point of fact, she usually dies immediately, or soon 
after ovipositing and cocooning, and knows nothing of her offspring or 
their dangers save by anticipative instinct, that foreordination in Nature 
which is everywhere so manifest in life habits. 
Perhaps one might be permitted to approach the problem from another 
direction, and suggest that instead of the instinct of the parasitic hymen- 
opter reacting upon the spider mother to cause increased cocoon safeguards, 
that instinct simply perceives the well armored cocoon and selects it as 
the one most secure for her own progeny. 
The cocoon of Agreeca brunnea (see Vol. II., page 124) is also well 
devised to preserve the enclosed eggs, and withal is overcoated by the little 
mother with a plaster of mud, which adds to the protection of armoring 
that of mimicry. Yet this spider’s eggs give hospitality to no less than 
six parasitic species, showing it to be especially assailable, or at least espe- 
cially available for such purposes. In this case, however, we can suggest a 
reason ; for although the spider’s cocoon is so well armored, the mode of 
suspending it (see Figs. 184, 185, Vol. Il.) permits the mother parasite to 
approach it with comparative ease, by crawling along the foot stalk from 
the plant on which it hangs. Indeed, speaking generally, one would infer 
that the cocoons of Tubeweavers and such other species as are placed 
