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BULIETIN OF WISCONSIN NATURAL HISTORY SOCIETY. VOL. 5, NO. 1. 
December 13, 1906. 
Combined meeting of the Biological sections. 
President Teller in the chair, and Messrs. Earth, Ernes, Colles, 
Doerflinger, Finger, Graenicher, Russell and Ward jiresent. 
Dr. Earth opened the discussion with his observations during the past 
year on the habits of wasp of the genus CraJjro observed in the vicinity 
of Milwaukee. The species collected were wood boring- in habits, but 
Dr. Earth stated that very satisfactory breeding tubes could be made 
from small glass vials, a tritle longer than the natural cell, but of the 
same diameter. The larvae are not easy to raise in captivity as the 
change of environment seems to affect them greatly. The humber of 
flies carried in varies among individuals of the same species, the num- 
ber being to some extent proportionate to the size of the flies. Some 
wasps seem to prefer large flies which they pack loosely in the brood- 
cell, while others select small ones which they store tig'htly together. 
He found that the duration of the egg stage was not always the same 
nor the time required for forming the cocoon. In carrying the captured 
flies the Crabros usually grasp them between the hind legs with some 
assistance from the middle pair of legs. They hold the prey very 
tightly, going with it into the nest head first. On a number of occa- 
sions after opening nests he found that the flies were able to move 
about and even crawl away. The fly upon which the Crabro's egg is 
placed was, however, never found to be alive. Dr. Earth also gave a 
list of the species of flies carried in, mentioning especially a Tachina 
fly {Winthe77iia Jf-pitstulata), and two species of Acroceridae belonging 
to the genus Oncodes. Eegarding the arrangement of the cells and 
galleries in the wood, Dr. Earth said that they were usually spiral, not 
always following the line of least resistance. There is usually a main 
gallery with smaller branches leading to the cells. The stinging habits 
of the Crabros were found to be simple, the fly being stung on the 
ventral surface of the thorax. When stuck by a needle in the same 
place, the speaker found that they were affected in nearly the same 
way, later reviving. When returning with their flies, the Crabros are 
never in a hurry to enter the nest, thus giving ample time for parasites 
to lay their eggs. In some cases Dr. Earth was sure the parasite must 
enter after the Crabro egg had been already laid. He had a number of 
parasites obtained from the various Crabros studied. 
After the speaker had finished his remarks, Dr. Graenicher said 
that he had been rather surprised to hear that species of Tachina files 
were captured by the Crabros, as he had often observed how easily 
