PARASITES OF SPIDERS AND THEIR EGGS. Bi 
From the above examples of life history, which are fairly characteristic, 
one may get the following summary of habits, which, while open to correc- 
tion at some points, is substantially accurate: 1. The parasite mother passes 
from point to point in search of a suitable host with a rapid, jerky, intense 
action; 2, discovering her victim she deposits an egg upon the 
Sum- abdomen, 3. and in so doing she will creep along the lines of 
Beis. spinningwork to the point where the spider is suspended. 4. When 
near her victim she backs down thereto and deposits but one egg 
upon each host, which is placed upon the abdomen close to the cephalothorax. 
5. In about two days the egg hatches into a footless, white larva, which in 
some cases creeps within the body, probably. by some of the natural open- 
ings, and becomes an internal parasite. 6, The external parasite fastens upon 
the dorsal base or dorsum of the anterior part of the spider’s abdomen, and 
in two or three days wholly consumes that soft organ, meanwhile growing 
rapidly, and then begins to spin its cocoon. 7. The cocoon is cylindrical, 
about six millimetres long and two thick, woven of open and loose white 
or yellowish silk, and is suspended to the spider’s web or other object by 
a slight band, braced beneath by a similar support. 8. The spinning occu- 
pies from one to three days, several days are spent in the pupal change, 
and in about a week the imago appears. 9. It is probable that some larval 
parasites which are hatched late in the autumn hibernate with their hosts. 
The habits of those parasitic Ichneumonids which infest spider eggs 
cannot be summarized with even as much satisfaction as the body para- 
sites, but the following may at least suggest something better. 
1. Soon after the spider mother has laid and enclosed her eggs, 
and sometimes probably during oviposition, the Ichneumon mother 
inserts her eggs, penetrating the cocoon case when necessary with 
her ovipositor, and leaving a number of eggs or the entire brood within 
a single cocoon. 2, Each egg harbors one parasite, which in certain species! 
enters it as soon as the larval appetite awakes and entirely destroys it. 
3. In some species it would appear that the larval parasites feed upon the 
eggs indiscriminately, and then spin stiff, close, white cocoons, through 
which the imago gnaws a hole and escapes from the spider cocoon in the 
same way. 4, These parasites are in turn exposed to parasitism from other 
members of the Ichneumonid family.? 
Egg Para- 
sites: 
_ Summary 
VIII. 
Mr. Howard has kindly furnished me a list of known American and 
European hymenopterous parasites of spiders. Some of these, together 
with those heretofore referred to, I have arranged as below, with a view 
1 Acoloides saitides Howard. 2 See Vol. IIL., page 395. 
‘Since this manuscript was prepared Mr. Howard has published his revised list and 
my table has been corrected thereby. 
