192 
THE USE OF GRAPE BAGS BY A PAPER-MAKING WASP.* 
By Mary E. MURTFELDT. 
As a premise to the observation here recorded, I may say that for a 
number of years the practice of inclosing the clusters of grapes in 
paper bags, to exclude the spores of black rot, has been very generally 
followed throughout St. Louis County. and especially in the vineyards 
of Kirkwood and vicinity. 
Last summer a peculiar shredding and perforation of the exposed 
sides of many of these bags attracted my attention, but was attributed 
to the poor quality of the paper. The present season a different and 
better quality of bags was procured for our vineyard, but early in July 
IT again noticed and was puzzled by the same appearance of wear. 
A few days after the matter was spoken of, my sister announced that 
she believed she had discovered the author of the mischief in the Rust- 
red Social Wasp (Polistes rubiginosus). While standing near a grape- 
vine she had been attracted by the faint sound of the tearing of paper. 
Supposing it to be a bird, attempting to peck the fruit, she made a mo- 
tion to drive it away and was surprised to find that instead of a bird it 
was the insect above named. In a few moments, however, it returned, 
and alighting upon the same bag began again, with the utmost energy. 
stripping off, with its jaws. fibers and layers of the paper. These were 
rapidly gathered, by the aid of the front tarsi, into a compact packet 
and finally borne away. 
These observations were in the course of the next two weeks repeat- 
edly verified. A critical examination of the fruit at that time, still hard 
and green, revealed not the slightest puncture even when exposed 
through the holes gnawed in the bags. The unavoidable conclusion, 
therefore, was that this wasp had made the important discovery that 
working over ready-made paper into nest-building material was easier 
than to manufacture it de novo from wood fiber. 
It may be added that as the paper used in the construction of the 
bags was probably made from wood pulp, the original material was the 
same, but the insect in appropriating it reaped the benefit of the initial 
processes of manufacture. 
I have had opportunity to examine but one nest of the species show- 
ing this adaptiveness since the above observations were made, but in 
this there seemed to me there were traces of the bag paper in the lighter 
and more yellowish color in portions of the walls of many of the larval 
cells. 
No other species of Polistes or Vespa have as yet been observed to 
* Read before the Section of Biology A. A. A. S., Washington, D. C., Aug. 22. 1891. 
ea 
4 
