66 
Psyche 
[March 
Fig. 3. Totals of male Dorylini trapped by an ultraviolet light trap at Legon, near 
Accra, grouped in 20-day classes. 
The periodicity of the total sausage-flies captured, corrected and 
grouped in 20-day classes, is shown in Fig. 3. The five most abun¬ 
dant species accounted for over 99.5 percent of the entire catch and 
the leading four (97.18 percent), when their numbers are plotted 
(Fig. 4), show markedly similar periodicities. Kendall’s index of 
concordance, W, was calculated, correcting for tied values: 
n (number of sampling classes) = 20 
k (number of species) = 4 
W 2 = 0.51 
X 2 = 38.76 
DF = 19 
0.01 > p > 0.001 
The value of p confirms that the similarities could scarcely be due 
to chance. The fifth species, Anomma nigricans, was producing 
males, as were the first four, more or less throughout the year. 
However, its peak numbers occurred in mid-September through 
early October (Fig. 5), and not March to May as in the first four. 
