56 R. E. DRAKE-BROCKMAN THE BLOOD-SUCKING DIPTERA 



mules and cattle were so molested by their attentions during the heat oE the 

 ■day that they gave up all idea of grazing. The female alone attacks animals, 

 the male obtaining necessary nourishment from the nectar of the wild flowers 

 which were plentiful there in the month of October, following the rainy 

 season. They start operations about 10 a.m., when the sun is high, and only 

 continue to annoy while the sun is shining. If the sun is masked by clouds 

 for even a short interval they slacken their attentions, and cease to bite 

 iiltogether if the day be cloudy. Animals annoyed by them crowd together 

 for protection, seeking the shade of the smallest bush or tree. This fly, 

 together with other members of the same family, is known to the Somalis by 

 the name of ^' Dug.'^ They do not consider its bite dangerous to their stock, 

 but they avoid the stretches of country which it frequents, as the animals, 

 instead of grazing, spend their time keeping the flies off, and in consequence 

 lose flesh rapidly. 



The two species of Hcematopota met with in this belt of country were caught 

 ■on the banks of the River Daro, a tributary of the River Wabi. One I caught 

 on my arm, and the remainder on the herd of bullocks which accompanied 

 the caravan. I never saw any on the ponies, mules or camels — they seemed 

 to prefer the cattle. 



On leaving Gamoji we ascended to Gurri Dagono (6800 feet), and travel- 

 ling in a south-easterly direction encountered no biting flies until Ginir was 

 reached. Ginir is the great trading centre for Eastern Abyssinia, and here 

 Stomoocys calcitrans abounded, and was very troublesome. 



Here we left the Arussi country, and descended to the valley of the River 

 Web^ and then followed the river to its junction with the Ganale and the 

 Dawa Rivers. At Odajida, on the River Dinnik, a tributary of the Web, I 

 found Hcematopota mactans on the cattle, but they were scarce. At Odhun, 

 I found Tahanus ditceniatus, a species I had not hitherto met with ; two or 

 three settled on me while in my tent, but I hardly think they had any inten- 

 tion of feeding. I caught three more of this same species at Gebidi-labba- 

 -dehd, on the Web, and at Malka Sala, on the Dawa. It settles with an 

 indistinct humming noise, which it makes while on the wing, and takes some 

 time before it settles down to feed. It is well known to the Somalis by the 

 name of " Bal ad,^^ and is considered by them to be dangerous to stock — 

 camels in particular suffering greatly from their onslaughts. Although human 

 beings are frequently attacked by them, no ill effects seem to accrue. From 

 Odhun to the junction of the Rivers Dawa and Ganale at Dolo (950 feet), 

 and all along the banks of the former, the '^ Bal ad '^ is more or less common. 



At Gebidi-labba-dehd, a species of Tahanus, T. tceniola^ was caught^ but it 

 was rare, as only one specimen was obtained. At Dolo and at Malka Duggah, 

 and, in fact, all along the Dawa River, Tahanus morsita^is was very plentiful. 

 At the former place another species of Tahanus was caught, but it has not yet 

 been identified ; only one specimen was obtained. This specimen is not 

 unlike T. morsitans, both in appearance and habits. Along the Dawa River 

 T, morsitans was very troublesome, the animals, especially the ponies, being 



