NOVEMBER, 1905. SOME OBSERVATIONS ON PARASITIC BEES. 
165 
August 21, 6 A. M. enable the insect to crawl around. The 
mandibles are, in size and appearance 
very similar to those of Ccclioxys (Fig. 5). 
August 23. The parasite is now spending- most of its 
time on the bee-bread, feeding. It is not 
quite as agile as previously, but still mak- 
ing biting movements when disturbed. 
These are always performed in the same 
characteristic manner. At first the mandi- 
bles are pushed deep down into the bee- 
bread, closed and held quietly in this posi- 
tion for a few seconds. After this they are 
retracted so as to leave only their tips in 
contact with the bee-bread, and then 
opened and closed several times in rapid 
succession. 
August 24. The larva has moulted. The mandibles 
are small and the lateral appendages have 
nearly disappeared. In its present form 
the larva does not leave the bee-bread, 
and the biting movements are not as pro- 
nounced as formerly. 
August 25. Parasite dead. 
A second nest of Melissodes tHnodis dug out on August 25, 
1903 furnished a cell with a larva of the parasite that had already 
moulted some time before. The lateral appendages were not in 
evidence in this larva, and it therefore seems probable that after 
the first moult has taken place, and the larva has begun a sede- 
tary life on the bee-bread these appendages gradually disappear. 
(Fig. 8.) In the cell under consideration no remains of a host- 
larva could be discovered, but the dead bodies of two more para- 
sites were found on the bee-bread. In this cell, as in the one from 
the first nest three parasitic larvae have been waging war on 
each other for the sole possession of the cell and its contents. 
The parasitic larva of Triepeolus helianthi with its powerful 
mandibles and its head-shield resembles very closely the larvae 
of our two species of Cmelioxys referred to in this paper. But in 
Triepeolus we become acquainted with a new feature in the make- 
up of a bee-larva, viz., organs of locomotion that enable the owner 
to leave the bee-bread and crawl around on the interior of the 
cell. One of these parasites on the smooth wall may be in a 
more favorable position to attack than one below on the bee- 
bread. 
