﻿223 



TABANIDAE ATTEACTED BY SCALE-INSECTS. 



Dr. J. W. Scott Macfie, Medical Officer at Ilorin, Northern Nigeria, has made 

 the interesting observation that a tree attacked by a Coccid of the genus 

 Ceroplastes served as a strong attraction to several species of Tabanidae, 

 including both males and females. He writes : — 



" I am sending a small lot of flies representing exactly a week's collecting from 

 one small ' Chedia ' tree in my compound, which I have just discovered to be an 

 abundant source of biting flies. The ' Chedia ' is very common all over the country ; 

 it exudes quantities of milky latex on the slightest injury, and bears small reddish- 

 yellow berries, but I do not at present know its scientific name. In my compound 

 I have several young trees of this species, but the one on which all these flies 

 were taken differs from the others in being heavily infested with a species of 

 scale-insect. It is quite a small tree, not more than 14 feet high, and the largest 

 of its branches is only 2-£ inches in diameter. The surface of all the branches is 

 more or less covered with old scales, and on the young growing shoots there are 

 fresh scales that attract swarms of ants, which march in columns up the tree-trunk 

 all day long. The flies, however, are never seen on these young shoots ; they 

 always appear suddenly and silently on the large branches over which they crawl, 

 slowly moving their fore feet to and fro laterally, as though they were sweeping 

 invisible atoms into the middle line under their probosces, which every now and 

 then they bend down, appearing to be feeding. So engrossed are they that it is 

 almost possible to catch them by hand. 



" I see, in the Sleeping Sickness Bulletin (No. 36), in the review of a paper by 

 Prof. Hine on North American Tabanidae, that 'many species of the family 

 Tabanidae have been observed feeding on the excretions of insects ' such as 

 ' aphides, scale-insects and Hemiptera.' One male ( Tabanus gratits), which I 

 dissected, had its stomach full of small yellow bodies which did not stain with 

 Griemsa's solution. The flies are only to be found on the tree in the day-time, 

 and especially when the sun is shining; I have never found them on the branches 

 at night. 



" It is noteworthy that my pony, tethered not 20 yards away, was quite 

 unmolested by flies at the very times when I was catching considerable numbers 

 on this ' Chedia ' tree. Indeed, until I observed this source I was able to get but 

 few specimens of biting flies here (Ilorin). It is, perhaps, a danger to have such 

 a tree in the vicinity of a house or stable, on account of its influence in attracting 

 blood-sucking insects, although the majority of the flies may prefer the diet 

 found on the tree to the meal of blood afforded by the horse." 



The specimens sent by Dr. Macfie comprised sixty Tabanidae, referable to 

 the following six species : — 



Tabanus pluto, Walk. 



... 



1 



— 



„ biguttatus croceus^ Wied. 



... 



3 



3 



„ taeniola, P. de B. ... 



... 



9 



11 



„ gratus, Lw. 



... 



15 



6 



„ lavevani, Sure. 



... 



3 



4 



Haematopota sp. nov. 



... 



3 



2 



