156 BULLETIN OF WISCONSIN NATURAL HISTORY SOCIETY. VOL. 4, NO. 4. 
discovered in one of the cells, at the same time a larva was noticed 
coming out of a second egg, and at noon a larva appeared from 
the third egg. These eggs had undoubtedly been deposited on 
July nth around noon, and we may therefore estimate the dura- 
tion of the egg-stage at about 66 to 72 hours. Such an egg is 
fastened by the tip of its slender process to the wall of the cell 
or the inner surface of the cocoon, and it protrudes free into the 
-cell-cavity or the cocoon-chamber if the cocoon has already been 
constructed at the time of oviposition. During the process of 
hatching the cephalic end of the egg is forced open and lifted up 
like a lid, and the head of the larva appears. After crawling out 
the larva still remains clinging to the egg-membrane by means of 
the enlarged anal segment. In this position it sways its body in 
different directions, as if trying to gain a hold, and it probably 
succeeds in sooner or later coming in contact with the body of the 
b>ee-larva, since the latter occasionally changes its position. One 
of these parasitic larvae was placed on a bee-larva, and it at once 
secured a hold with its mandibles. 
The most conspicuous part of the primary larva of Leucospis 
affinis is the large head with its rather firm covering of chitinous 
substance. In addition to the head the body consists of thirteen 
segments adorned with four rows of long, stiff hairs, viz : a lateral 
row on each side along the lower surface, and one along each side 
above. Fabre also describes such hairs in the larva of L. gigas, 
and he refers to those along the ventral surface as locomotory 
organs ("organs ambulatoires") , although he witnessed the curved 
larva walking around on the bee-larva in a similar manner as a 
so-called measuring worm (larva of a Geometrid-moth) walks 
around on its plant. In our species of Leucospis we notice the 
same peculiar movements. At first the head obtains a hold with 
the mouth parts, and then the curved body is drawn forward, 
and brings the anal segment near to the head. In turn the anal 
segment holds fast to the surface, the head is pushed forward for 
a new hold and in this manner the larva moves over the surface. I 
can not see any reason for regarding the lower hairs as organs of 
locomotion as Fabre has done in the case of L. gigas. They are 
probably tactile organs, and furthermore, they may serve the pur- 
pose of protecting the small and delicate larva from being crushed 
between the bee-larva and the surrounding walls. 
