228 Annals Entomological Society of America [Vol. IX, 



were preparing to retire, while in the former one could learn but 

 little more than the position of the insect in relation to its 

 surroundings when already asleep. A few early morning trips 

 afield were very productive. 



WASPS. 

 Chalybion caeruleum Linne. 



A congregation of about thirty of these steel-blue wasps was 

 discovered on the under side of an overhanging rock on the 

 bluffs overlooking the Meramec during July, 1908. It was 

 about 10:30 o'clock in the morning and very dark, due to an 

 approaching storm. It was puzzling to see these wasps, 

 usually of solitary habit, all huddled together in a very small 

 space. They were inactive but alert enough that when an 

 attempt was made to take them they all flew away, but soon 

 returned to the same spot. Three times they thus persistently 

 returned to the identical spot when disturbed. The mud nests 

 of this species are usually situated in a sufficiently sheltered 

 place that it is not necessary for the wasp to seek shelter else- 

 where; hence there must be some other reason for each one 

 leaving her solitary nest and all coming together with one accord 

 and seeking the appointed meeting-ground and the company 

 of others. There were many other sheltered nooks among the 

 rocks, but no isolated wasps were in them; this leads one to 

 believe that this assemblage was not due to mere accident. 



In 1913, I had another opportunity to study these wasps 

 at Lake View, Kansas, and the results of these observations 

 proved that gregariousness in a modified form does occur in 

 this species. This wasp is not gregarious as is the cockroach, 

 spending almost every hour of its life in the community of 

 others, but in a more anthropomorphic sense. Our nervous 

 little blue wasp only after a day's hard toil of gathering mud and 

 constructing her nest of it mouthful by mouthful, of hunting 

 and paralyzing and carrying home a supply of spiders, at the 

 ■close of day leaves her work and seeks the chosen spot, there to 

 enjoy the company of other workers who have gathered there 

 likewise to spend the night. The males were also there in 

 numbers equal to the females, but how or where these shiftless 

 fellows spent the day, no one knows. 



