310 JAS. J. SIMPSON—ENTOMOLOGICAL 
TABLE A. 
Annual Rainfall in Northern Nigeria (in inches). 
rs | 3 
5 5 6 
3 oy q ol te EB $ 
2 a 6 S 5 s 5 é g S s a 5 
= I 3 g ic z ic a 3 5 3 S a 
<4 A a i a oa 2 ca i N N A 4 
| 
1906 34°60 51°83 60°39 | 61:05 | 49:00 
1907 18°11 | 19°86 | 25°62 | 27°55 36°68 | 37:28 | 37°16 54°74 
1908 | 23°70 | 22°30 | 20-44 | 34°86 | 53°77 | 47°88 | 44°12 | 46°46 | 55°15 | 48°78 | 45:48 | 55°46 | 58°77 
1909 | 23:03 | 31°89 | 29°72 | 49°03 | 44°26 | 43°23 | 65°14 | 55°77 | 60°67 | 58°89 | 55°80 | 65°18 | 66°85 
1910 | 18:21 | 19°53 | 23°11 | 26°81 | 38°67 | 38°86 | 45°49 | 47-98 | 53°01 | 53°44 | 53°80 bL14 5644 
54:03 | 55°10 | 60°69 
Mean | 21°65 | 22:96 | 23°28 | 34:08 som 43°32 860 
50°07 | 51°53 sets 
The above table reveals several important facts, but none more obvious 
than the striking difference in the rainfall at the various stations. The maximum 
rainfall recorded during these five years is 66°85 inches, at Ankpa in 1909, and 
the minimum is 16°87 inches, at Geidam”* in 1910, while the difference between the 
rainfall at Geidam and Ankpa in 1909 amounts to 45°57 inches, or more than 
twice the total rainfall at the former station. 
A study of the mean annual rainfall at the various stations shows that there is 
an almost regular increase from the north southwards. At one end of the scale 
stand Sokoto, Katagum, Maiduguri and Geidam, in the extreme north, and at 
the other Hlorin and Ankpa in the south. 
TABLE B. 
Monthly Record of Rainfall in Inches for 1909 and 1910. 
1909. 
Srarron. | Jan | Feb.| Mar.| Apr.| May. | June.| July. | Aug. | Sept. | Oct. | Nov. Dec. 
| | | 
| Geidam —| —]|] —] 1:05) 1:42] 439] 4:79) 7-70) 1:83) 0-08] — | 0:02 
| Katagum .. —| —]| —]| 011} 3:98] 4:05] 4:02) 632) 417) 0:33}; — | 0:05 
| Birnin Kebbi —| —| —]| 2:92) 3:31) 3:35] 2°37) 12°98) 2:34] 0-43) —| — 
| Sokoto —| —]| — | 155] 1:52) 434] 8-72) 10°61] 2:52) 040; —| — 
Maiduguri —}| —| —/1:01) 075] 4:04) 533) 12:06] 866) 004; —} — 
| Nafada | —| —| — |] 359] 1:29) 512) 866) 10°82) 6:89) 0:90) —) — 
| Bauchi ;} —| —| —| 3:99} 2°53} 5°64] 10°76) 11:16) 8-73) 0-42; — |) — 
| Yola .. — | — | 0:35) 4:33] 3:90} 10°13] 6:23) 756) 8:23] 3:35) — | 0:18 
Keffi ... — | 1:13] 3°12) 3:39} 4:94] 652] 9:10) 14:14) 4:48) 2:20) —| — 
| Kano | —= | — | 009) 1°75) 8°70) Say 9:01) 17:72) 96:83) ONT pe Oeb 
[elise se - | — | 0°70) 2°75) 640) 848) 5:23) 5:01) 757 8°89} 7:49] — | 0°78 
Baro ... ... | 1:06} 0°80} 3:00| 6°74) 3:49) 6°73) 8-19] 16°92) 6°60) 1°88) — | 0°36 
| Zaria... we. | — | 0:36) — | 3:56] 5°79) 6:51) 13°11) 16°62) 6:61) 1°74; — | 1:50 
| Zungeru..._ | 0°38 2:02) 4:66] 3:27|) 6:09} 12:88} 11:24] 14:27| 2:78); — | 1:30 
| Kontagora ... | — | — | 2°51] 6-42] 2:02} 6:22/ 13:33| 13:12} 12°87] 3°83) — | 0:35 
Lokoja .-- | 0°04} 1:32] 5°19] 6:80} 8:20] 6°90] 10°35] 12°13} 10°37] 2°61) — | 1:23 
Jlorin .- | 0°79} 1:18} 5°30] 7°78] 7:12) 8:32] 9°49) 4:92] 14:12] 4°74] 0:23) 1:19 
Ankpa ... | 0°39) — | 3°64] 8°63} 14:02) 7:72] 4:42) 812) 10-23] 8:80) — | 0:88 
~ # As the records for Geidam are available only for 1909 and 1910, it has been omitted from 
Table A, but is included in Table B. 
