1966] 
Nutting — Paraneotermes 
137 
Figure 2. Flight season of Paraneotermes simplicicornis in relation to 
rainfall, weekly mean temperature and relative humidity at Tucson, Ari- 
zona, in 1963. Dates showing 0.1" actually indicate amounts from a trace 
to 0.1" of rain. Flights began when mean temperature remained above 
about 23 °C. The upper section shows the numbers of alates observed on 
each date during the flight season from June 15 to Aug. 19. No observa- 
tions were made between June 24 and August 1. Data on the maturation 
of alates were obtained from two colonies, one in the laboratory and one 
in the field. 
few simple correlations are apparent, however, and may provide a 
basis for determining the cues which are actually used by Paraneo- 
termes for initiating both its annual flight season and daily flight 
periods. 
T emperature 
The timing of the flight season in relation to weekly mean tempera- 
ture and relative humidity for two years is plotted in figures 1 and 
2. Flights began when the weekly mean temperature remained con- 
sistently above about 23 C C, while later in the season means reached 
as high as 29.9 0 (’62) and 30.6°C (’63). The seasons ended during 
weekly means of 25.9 0 (’62) and 25.4°C (’63), leaving three and 
seven weeks in these years before falling to 23 °C. At this point it 
might be mentioned that the areas under the curves for the two 
years studied — taken arbitrarily from the lowest weekly mean of 
the winter to the date of the first flight (figs. 1 and 2) — are very 
close as measured with a planimeter. This has suggested that it 
Relative Humidity, % (weekly mean) 
