August, ’20] 
PARMAN: INSECTS AND STORMS 
343 
The following observation gives some light on the effect of barometric 
pressure on the death rate of adult C. macellaria, showing that the 
adults apparently will not chill and die under the effect of a rising 
barometer as under a lowering barometric pressure. The adults under 
observation on November 24 were taken in the open and put in a cage 
November 20 and 22, a total of 366. The adults under observation 
November 27 were taken under the same conditions November 25 and 
26, a total of 500. Between noon and about two o’clock on each date 
observations and counts were made of the dead flies on the floor of a 
cloth cage 2 ft. cube with board bottom, this cage being inside of a 6 ft. 
cube cage made of screen wire. November 24, the first cage contained 
87 flies alive and 279 dead flies. Nov. 27, 83 dead flies were taken from 
the second cage and the others became active in a warm room. Thus 
showing a 76.2 per cent mortality in the first case under a falling ba¬ 
rometer as compared with a 16.6 per cent mortality in the second under 
a rising barometer. It is believed that other conditions could not have 
caused this wide difference in mortality. The following table gives the 
weather conditions under which the observations were made: 
1919 
Temperature 
Barometer 
Humidity 
Date 
Maximum 
Minimum 
8:00 A. M. 
8:00 P. M. 
Maximum 
Minimum 
Nov. 
23 
75 
61 
29.45 
29.15 
93 
65 
24 
70 
55 
29.05 
28.90 
98 
87 
26 
79 
48 
29.05 
29 00 
87 
36 
27 
54 
48 
29.25 
29.35 
98 
86 
Observations made at lights and at room windows at nights indicate 
that insects attracted to lights are more active during high barometric 
periods and especially while the barometer is rising. No specific 
determinations have been made to indicate the relative degree of reac¬ 
tion of different species under any particular condition. 
Bred adult Diptera tend to emerge on periods of rising barometer, 
the heavy emergences apparently always have been during high barom¬ 
eter. Trappings and observations indicate that Muscoid diptera are 
most abundant during long periods with slight variations in barometric 
pressure, provided, of course, temperature, humidity and rainfall are 
favorable. 
Migration of Lybithea baclimanni was observed during the summer 
and fall of 1916 to take place after storms which indicates that the 
flights were during high barometric pressure. 
