138 
Psyche 
[June-August 
ATTACKS OF VESPA COMMUNIS DE SAUSSURE ON 
HYPHANTRIA CUNEA DRURY. 
By M. T. Smulyan. 
U. S. Bureau of Entomology, Melrose Highlands, Mass. 
The wasp attacks reported here occured during September 
1923, at Roycefield, N. J., and were made on fall webworm 
larvae {Hyphantria cunea Drury) which had been collected in a 
number of localities for parasite study purposes. The wasps 
(Vespa communis De Saussure)i appeared, suddenly and in 
large numbers, as the first collection of the webworms was being 
examined out of doors, and they literally threw themselves 
upon the caterpillars, and their attacks were so persistent and 
savage that all efforts to drive them off, although it resulted in 
the death of many of them, were fruitless. The attacks began 
very early in the month, and they were continued at intervals — 
in connection with each out of door examination of the web- 
worms — throughout the ten-day collecting period. Attacks 
upon the caterpillars were made also while they were in a more 
or less open, near-by shelter, where they had been placed in 
rearing trays, and the wasps exhibited the same degree of ferocity 
and voracity here. They attacked here not only at the feeding 
of the caterpillars, when the trays were uncovered, but through- 
out the greater part of the day — through the screen covers — 
whenever caterpillars appeared on the undersides of the latter; 
and they continued this, although in decreasing numbers, until 
the last week of September when following a two or three day 
period of cold weather they disappeared altogether. 
The wasps, it should be added, apparently made no at- 
tempts to carry off the caterpillars. Nor, as far as could be 
seen, did they malax them. They would precipitate themselves 
upon them, pierce the integument with their mandibles, and 
consume the liquid and softer parts. 
^Determined by Dr. J. Bequaert of the Harvard University Medical 
School, on the return of the writer to Melrose Highlands, Mass. 
