1. Temperature pairs of x, the coldest and y, the warmest months of the year for N(w) = 1872 world-wide meteorological stations, were plotted with y as ordinates and x as abscissae. This produced a subelliptical scatter with its Major Principal Axis inclined at tan-1 0.34 relative to the x-axis. 2. Distribution maps of biological species were considered in terms of the same two temperatures, recorded at a subset N(s) of the meteorological stations representing the total world distributions of each particular species. 3. When y was plotted against x, the scatters so obtained for 35 species, had Major Principal Axes inclined at angles in the range tan-1 -0.02 to tan-1 0.85 relative to the x-axis. 4. Subelliptical confidence regions, representing a measure of the temperature distribution for each species, were constructed about calculated points on the Major and Minor Principal Axes. 5. These subelliptical confidence regions in turn permitted the representation, on a geographical map, of that part of the total world area in which temperatures would be suitable for each species. 6. The technique is applicable wherever detailed knowledge of the effective temperature limits for a biological species are required-whether in agricultural planning, the interpretation of the consequences of climate change, or the estimates of past temperatures at fossil sites.