﻿154 JAS. J. SIMPSON — ENTOMOLOGICAL 



In Table E I have collected the records of monthly temperatures for thirteen 

 stations in the Colony, giving (1) the maximum for one day during each month, 

 (2) the minimum for one day during the month, (3) the average maximum for the 

 month, and (4) the average minimum for the month. The stations have been 

 arranged in descending annual maxima. It is unnecessary to enter into any 

 detailed discussion of the various data here presented, but I should like to draw 

 attention to some of the major features : — 



(1) The means of the average monthly maxima all lie within a very circum- 

 scribed compass ; at one extreme stands Calabar with a mean of 88*3° F., and at 

 the other Degema with a mean of 83*6° F. 



(2) The means of the average monthly minima show a similarly low range ; for 

 example, Lagos with 74*9° and Ibadan with 63*8° are the most diverse. 



(3) The difference between the maxima for the various months is comparatively 

 slight. Thus, the greatest divergence was'21° at Bonny (99° in April and 78° # in 

 July), while at Oshogbo the difference was only 13°, and at Brass it was least of 

 all — namely, 4°. The range is least in the delta region, and greatest in the north. 



(4) The same is true with regard to the range in the minima. 



(5) The difference between the maximum and minimum in any one month is 

 greatest in the dry season, and, generally speaking, more in the north than in the 

 south. 



The extremes of shade temperature recorded for S. Nigeria are 46° and 110° ; 

 the highest average of maximum shade temperature is 93*2° at Olokemeji, and 

 the lowest average of minimum 59*40° at Ibadan, both in the Western Province. 



The mean height of the barometer at sea-level is about 30 inches, with a total 

 range of 0*10 inches between the highest and lowest readings during the day-time. 



It must not be considered that these few observations by any means exhaust 

 the deductions to be drawn from these tables, but they constitute the most impor- 

 tant from the point of view of the distribution of the insect fauna, and when these 

 are borne in mind, many points, otherwise obscure, will be found to be correlated 

 with the general climatic conditions. 



The whole may be recapitulated thus : — 



(1) Stations in the same latitude have similar rainfalls. 



(2) The rainfall is greatest successively at Calabar, in the Niger delta, and in 

 the lagoon region along the coast, and diminishes from the south northwards, 

 except along the river basins and in the hilly regions. 



(3) Where the rainfall in the north, e.g., at Ondo, is greater than in the 

 surrounding country, it is due to a greater intensity during a few months, and not 

 to an increase in the number of rainy months. 



(4) The rainfall curve is of the equatorial type — that is, there are two annual 

 maxima and minima, the maxima tending to fuse into one in the northern parts 

 of the Western Province. 



(5) The dry and wet seasons are not very definitely separated, but the rainfall 

 is almost negligible from November to February, and the duration of this dry 

 season increases from south to north. 



* It is not improbable that this record is much too low. 



