132 
Psyche 
[June 
Paraneotermes simplicicornis is apparently unique among the dry- 
wood termites (Kalotermitidae) for, although the reproductive cen- 
ter has never been found, it is fundamentally subterranean in habit. 
Over its known range in the deserts from southern California and 
northern Baja California to southern Nevada, southwestern Texas 
and northern Sinaloa, Mexico, it typically attacks moist wood in or 
on the ground in washes and canyons. Small living trees are even 
cut off' just beneath the soil on occasion. A detailed account of the 
biology, distribution and taxonomic relations of this most interesting 
termite was published by Light in 1937. At that time swarming had 
never been observed, nor has it been reported since. 
Study area and methods. — Nearly all the flights were ob- 
served within an area of less than an acre in north-central Tucson, 
Arizona, at an altitude of 2400 ft. This part of the valley floor is 
now about equally divided between creosote bush desert (Larrea 
tridentata) and small residential developments. Three to four feet 
of fine-textured alluvium overlies a narrow zone of friable caliche 
or hardpan. The mean annual precipitation of 10.9 inches is almost 
equally divided between a summer (July-Sept.) and a winter (Dec.- 
March) rainy season, characteristic for most of the Sonoran Desert. 
Although the mean annual temperature is I9.6°C, it is of little sig- 
nificance unless it is realized that daily fluctuations of 15 0 are 
common and of 2i°C not unusual. In 62 years the highest recorded 
temperature was 44.4 0 (July, 1953, and several other dates), the 
lowest — I4.4°C (Jan., 1913) (Sellers, ’60). 
Considering our scant knowledge of the types of sense organs with 
which the various castes of termites are equipped, much less the in- 
formation which they are collecting, it is still far from clear what 
environmental factors should be measured, to say nothing of the 
necessary degrees of accuracy. Hence, many of the methods used 
here are admittedly exploratory and probably crude. Certain refine- 
ments have already been made and others are continually suggesting 
themselves. For example, it would probably be desirable to measure 
many microclimatic parameters; however, their usefulness will de- 
pend upon a much greater knowledge of the termites and their pre- 
flight activities within and near the nest than is now available. 
Starting in January, i960, continuous records of air temperature 
and relative humidity have been made in the study area with a Ben- 
dix-Friez Hygrothermograph, Mod. 594 (maintained to an accuracy 
within approximately z±i°C from —12 to +43°C and ±5% from 
O to 100% RH). The instrument is sheltered six feet above the 
ground. Weekly mean temperatures and relative humidities were 
