1948] 
Bailey — Hybomitracincta 
179 
season, i.e.) of temperature, relative humidity, and light 
conditions. Another year an attempt will be made to 
accumulate more detailed information of this nature. 
Table 1. 
Date 
Hour 
Males 
taken 
Light 
Remarks 
7- 7- ’48 
3:30 p.m. 
1 
8 
9 :40 a.m. 
3 
15 
2 :30-3 : 30 p.m. 
7 
17 
12:30-1 :30 p.m. 
. 0 
18 
8:30-8:45 a.m. 
2 
W arm, humid, high 
clouds. 
19 
3 :45 p.m. 
4 
High overcast. 
20 
1 :30 p.m. 
3 
10,500 ft. candles 
2 : 20 p.m. 
1 
21 
12-12 :30 p.m. 
0 
5,500-12,000 ft. c. 
Very warm, humid, 
cloudy. 
5 : 10 p.m. 
2 
3,500 ft. candles 
Missed a third fly. 
22 
4:00 p.m. 
1 
27 
2:05 p.m. 
0 
6,000 ft. candles 
29 
2:00 p.m. 
4 
10,500 ft. candles 
Hot and clear. 
The light values were all determined with a G-E ex- 
posure meter (Model DW-58) using the 100:1 incident 
light mask. Readings were taken with the meter held 
vertically (openings up) at shoulder height. Values of 
300 :1 may be obtained with this instrument by covering 
two of the three mask apertures. This is necessary for 
readings above 7,000 foot candles. 
The station lies in the Neponset River Reservation 
along Route 128 in Canton, Massachusetts. The area is 
somewhat below the road level and the plant cover con- 
sists of clumps of young deciduous trees, shrubs, and 
evergreens with grassy glades interspersed. A bridle 
path, with evidence of slight usage, makes an irregular 
loop through the part under consideration. It was only 
beside the bridle path in two of the larger open places 
that hovering flies were seen. The two sites are sepa- 
rated by a wooded area a few hundred yards wide. About 
80% of the flies were taken at the spot nearest the 
highway. 
Here the first male was encountered. He was hovering 
