NOVEMBER, 1905. SOME OBSERVATIONS ON PARASITIC BEES. 
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serted burrows of coleopterous larvae in partly decayed 
branches or logs laying on the ground. After clearing out such 
a burrow the bee proceeds to construct its cells with pieces cut 
out of green leaves in the manner characteristic of the leaf-cutter 
bees. Such a cell is about half filled with bee-bread, and an egg 
5mm. in length deposited on the surface. One or more cells 
are constructed, and the opening of the nest filled with minute 
particles of chewed wood. 
A nest of this species from the neighborhood of Milwaukee, 
was opened on September 3, 1903, and found to contain two 
cells, one of which as later events showed was infested by 
Coelioxys. A visit of Ccclioxys lucrosa to this nest was noted 
the day before. The following gives an account of the happen- 
ings inside of the infested cell. 
September 3, 1902. Host-egg present, no parasite visible. 
September 5. The host-larva hatches in the afternoon. 
September 8. Host-larva alive, has grown considerably. 
Around noon the head of a second larva 
(Cadioxys) with extremely long, slender, 
and curved mandibles (Figf. 5), makes its 
appearance from out of the depth of the 
rather soft food-supply, biting aimlessly 
in different directions, and within a short 
time piercing the body of the host-larva. 
Later on the parasite withdraws, and 
feeds on bee-bread, opening and closing 
its long mandibles which seem to be 
rather unfit for this pupose. The attacks 
on the host-larva are renewed from time 
to time, and during: these the parasite is 
seen sucking- the body juices of the 
victim. The latter finally dies from the 
repeated attacks without ever having of- 
fered any noteworthy resistance. It does 
not seem possible that the larva of the 
leaf-cutter bee with its comparatively 
small mandibles could ever successfully 
resist an adversary armed with such for- 
midable weapons of attack. The head of 
the parasite has a hard brown covering: 
*This species seems to be C. lucrosa, Cress, but it may prove to be 
an undescribed species. 
