550 SIDNEY I. KORNHAUSER 
over the twig, and finding the nymph would oviposit just as in 
nature. This procedure was continued by renewing the nymphs 
until the Aphelopus was exhausted. She might oviposit again 
the next day, laying in all from twenty-five to fifty eggs, gener- 
ally one in each nymph. It was found best to work the para- 
sites as hard as possible the day they were captured, for they 
were most active then and would live only a few days in the 
laboratory. One lived five days, but thatwas unusual. The 
only successful way to capture the adult female Aphelopus was 
to place the mouth of a small vial over the individual as soonas 
she was discovered running over the bark, and thus try to corner 
her so that she would run up into the vial. One must not hesi- 
tate a second nor await a more favorable opportunity, for, 
should an ant come along, the parasite for which one may have 
been hunting several hours would hop or fly in terror. Aphe- 
lopus has a keen fear of ants, especially of Formica. This was 
tested in the laboratory by putting an ant and an Aphelopus into 
a tube. The ant immediately took the offensive, showing that 
an enemy of Thelia is not to be tolerated. 
When one dissects, under a high-power binocular microscope, 
a nymph which has just been stung, one will find a thin-shelled 
oval egg, 145u in length and 60u in diameter, and also several 
spheres covered with a chitinous shell and filled with yolk-like 
material. These spheres are developed in the female Aphelopus 
from single cells in a sack-like pocket ventral to and leading 
into the posterior portion of the oviduct, Just below the opening 
of the spermatheca. The function of the spheres, which vary 
from 25u to 35u in diameter, has not yet been determined. The 
egg! absorbs fluid from its host and the thin shell swells. Within, 
total cleavage takes place and the sphere of cells formed soon 
develops into a polygerm mass. This mass becomes oval, and 
then angular and irregular in outline, as it starts to form branch- 
ing chains of embryos. These chains are composed of spheres 
connected and covered by a placental envelope several cells in 
1 A detailed study of the cleavage of the Aphelopus egg and the formation of 
the polygerm is contemplated, suitable material having been secured from lab- 
oratory-stung specimens during the past summer. 
