( 1^1 ) 



IX. Oil Lepidoptcra from the White Nile, collected ly Mr. 

 W. L. S. LoAT, F.Z.S. ; together vjith further notes 

 on Seasonal Dimorphism, in Butterjiics. By Dr. 

 Frederick A. Dixey, M.A., M.D., Fellow of Wad- 

 ham College, Oxford. 



[ReaJ March IStli, 1903.] 



Plate VIT. 



Mr. W. L. S. Loat, during his tenure of office as super- 

 intendent of the Nile Fish Survey under the Egyptian 

 Government, spent more than three years in a scientific 

 investigation of the waters of the JNile and its tributaries. 

 Though his biological activities were mainly engaged in 

 other directions, he took several opportunities of collecting 

 butterflies; and the specimens captured by him in April 

 lUOl, and in January and March 1902, are in many 

 respects of great interest. Tliey are generally in excellent 

 condition, and are accompanied by ample data ; but the 

 collection (which has been liberally presented by Mr. Loat 

 to the Hope Museum at Oxford) derives what is perhaps 

 its greatest value from the fact that the specimens are 

 marked in such a manner as to allow all those caught at 

 one time and in one spot to be grouped together. The 

 captor informs me that on these occasions no voluntary 

 selection was made on his part ; that he tried, in fact, to 

 catch all he saw ; so that each of his " bags " may be taken 

 as a fair sample of the butterfly life that was at that 

 particular time on the wing. 



The localities of Mr. Loafs captures are as follows :^ 



I. White Nile ; Gharb-el-Aish, near Kaka ; about 



UN. Lat. 

 II. White Nile ; near Kaka ; about 10' 80' N. Lat. 



III. Bahr-el-Gebel (Nile); near Mangala; about 5' 



N. Lat. 



IV. Bahr-el-Gebel (Nile); Gondokoro; 4" 43' N. Lat. 



Several of the species obtained from all these localities 

 are well known to be seasonally dimorphic. As will be 

 seen later, the present collection contains a preponderance 



TRANS. ENT. SOC. LOND. 1903. — PART II. (JUNE) 10 



