August, ’20] 
PARMAN: INSECTS AND STORMS 
339 
OBSERVATIONS ON THE EFFECT OF STORM PHENOMENA 
ON INSECT ACTIVITY 1 
By D. C. Parman, United States Bureau of Entomology 
The discussion will deal primarily with the effect of barometric pres¬ 
sure on insect life as other storm phenomena—wind, rainfall, tempera¬ 
ture, atmospheric moisture, etc.,—have been more fully studied and 
discussed in general literature and time and space will not allow more 
than brief reference to these to make the matter clear. No experi¬ 
mental data have been gathered, all observations being made in natural 
surroundings and in cages used in other experimental work. Most of 
the observations have been made on Muscicls and related diptera, only 
general notes being made on other insects in the field and at lights. 
Until the fall of 1916 no barometer was available at the Uvalde, 
Texas, laboratory where the observations recorded herein were made. 
This permitted only of studies of the daily map of the Weather Bureau 
in connection with records made on insect activities. In the fall of 
1916 a compensating aneroid barometer was obtained and since that 
time regular readings have been made at 8:00 a. m. and 8:00 p. m. with 
special readings at time of storms. 
The first observation made on a storm of any severity was on the 
West Indian hurricane which passed over southwest Texas on the night 
of August 18, 1916. Some of the more significant data relating to this 
storm will be given from an extract of the “Monthly Weather Review” 
of August, 1916, and this publication should be consulted for fuller 
details. “The tropical cyclone passed inland between Corpus Christi 
and Brownsville the afternoon and evening of the 18th. After passing 
inland a short distance south of Corpus Christi the cyclone continued 
to move in a west-northwest direction, reaching Del Rio, Texas, at 
about 7:30 a. m. local mean time August 19, with a minimum pressure 
of 28.69 inches. Since it passed Corpus Christi, 200 miles distant, 12 
hours earlier, we may assign a movement of about 17 miles per hour. 
The recovery of the pressure after the passage of the center of the storm 
was extremely rapid. . . . We must consider that it dissipated 
over southwest Texas during the daylight hours of the 19th. 
It is worthy of note that all of the tropical cyclones of August, 1916, 
were characterized by remarkably small diameters and naturally ex¬ 
tremely steep barometric gradients near the center only. . . . And 
the fact that the centers did not closely approach any of the net¬ 
work of land stations except for a very brief period, the location of 
the center of the storms in each case was a very unsatisfactory matter 
. . . (Corpus Christi). The barometer reached its lowest point, 
1 Published with the permission of the Chief of the Bureau of Entomology. 
