OCT. 1906. HABITS AND LIFE-HJSTORY OF LEUCOSPIS AFFINIS SAY. 
157 
Fabre often found two or three and in one instance even as 
many as five eggs of Leucospis gigas in the same cell of a mason- 
bee, but never more than one primary larva. He always observed 
this larva making repeated excursions over the body of the bee- 
larva, and even around the inner wall of the cocoon, and he was 
led to believe that these were undertaken for the purpose of de- 
stroying any rival egg or eggs that might be present in the same 
cell. Later on he witnessed the destruction of the remaining 
eggs by the first-born larva. I have not yet come across more 
than one egg of L. afiinis in an Osmia cell, but the number of such 
cells under observation has been altogether too small. Judging 
from our acquaintance with several other hymenopterous parasites 
of bees, as also from the behavior of the primary larva of L. affmis, 
we may feel assured that in this species also more than one egg 
may be deposited in a single Osmia-cell. The primary larva of 
this species shows a marked degree of restlessness, and spends 
most of the time crawling over the Osmia-larva or even leaving 
the latter and moving around on the wall of the cell or cocoon. 
We are informed by Fabre that the corresponding trips of L. gigas 
around the wall of the cocoon of the mason-bee are made for the 
purpose of destroying the rival eggs. The size and strong build 
of the head in the primary larva of our affinis seem to me to 
indicate that such a larva is destined to undertake not only the 
crushing of harmless eggs, but also the destruction of an equally 
powerful rival larva. I desired to study the attitude of two such 
larvae toward each other, and placed them together with an Osmia- 
larva in a small glass-tube of the same size as an Osmia-cell. 
During the day one of the larvae attacked and killed the other one 
and sucked its contents, and in the evening nothing was visible of 
the conquered one but the shrivelled remains. The bee-larva 
serves as food for one parasite only, and when more than one egg 
has been laid in a single cell, only one larva issuing therefrom can 
survive. 
The first moult causes some considerable changes in the appear- 
ance and behavior of the larva, and in its new form it is called by 
Fabre a "secondary larva" (Fig. 5). The bulky head is replaced 
by one smaller in size and with less chitinous covering, the long 
hairs disappear more or less, and the larva leads a quiet life on top 
