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BULLETIN 'OF WISCONSIN NATURAL HISTORY SOCIETY. VOL. 3, NO. 4. 
and forms a conical mass with the slightly curved egg - of 2 to 3 
mm. length on top. The newly hatched larva has its head 
directed downward towards the base of the bee-bread. 
During the month of July, 1903, seven nests of this species, 
harboring the parasite Stelis sexmaculata either in the egg or 
larval stage were procured, partly from the surroundings of Mil- 
waukee, partly from Cedar Lake (Washington Co.). Of the 24 
cells in these nests 15 were infested by Stelis, a percentage of 62. 
In the following I offer a brief account of the observations 
made on one of these cells, as taken from my notes: 
July 9, 1903. Nest collected at Milwaukee contains 4 cells. 
Third cell (from below) with a parasite. On top 
of the bree-bread an Alcidamea larva, about 3 
days old. On the side of the bee-bread, about half 
way up a Stelis larva feeding on bee-bread. It 
is smaller then the host-larva, and its head is 
directed upward, and towards the posterior end 
of the latter's body. 
July 13. The parasitic larva has grown considerably but 
is not as large as the host-larva. At 1 P. M. the 
parasite moves upwards a short distance, comes 
in contact with the host-larva, and secures a hold 
on the latter's side behind the middle of the body. 
The victim at first makes an effort to free itself, 
but offers no serious resistance. The parasite re- 
mains in the same position the whole afternoon, 
sucking the liquid contents of the host's body. 
The latter gradually perishes, and shrivels. 
July 14. The parasite has released its hold on the dead 
host-larva, and is feeding on bee-bread. It has 
lately increased very much in size. From now 
on the parasite does not pay any more attention 
to the remains of the host. 
In the cell just considered a single parasite was present, but 
in a nest collected at Milwaukee, July 15, 1903, a cell was come 
across with 3 parasitic larvae, all of them on the same side of the 
bee-bread as the head of the host-larva. One of them was sit- 
uated above the middle, not far below the host-larva, the second 
was lower down and directed laterally and the third was below 
the second and quite close to it. In the evening the third parasite, 
which throughout the day (July 15), had been partaking of bee- 
6. D. Sharp. Loc. cit., p. 20. 
