972 CAPT. STANLEY S. PLOWEK ON THE [Dec. 18, 



very pale olive-brown with on each side a black longitudinal 

 line, sides rich reddish brown. Underneath head and thorax pale 

 grey. Underneath abdomen pale reddish brown, except centre 

 of last three segrneuts which are dark brown. Legs : basal seg- 

 ments grey, remainder reddish brown, except front pair, which 

 are black underneath and marked with black above distally. 

 Antennae black. Biting-organ : anterior shorter portion white, 

 posterior or longer portions black. Wings transparent, reddish- 

 brown veins. 



We first met the Seroot on the 16th March a few miles south 

 of the Abu Zeit ford, on the 17th and 18th we again observed it. 

 On the 23rd at Grabt-el-Megbahid it was numerous, as it was also 

 on the Zeraf and Ghazal rivers, but none were noted on the Bahr- 

 el-Jebel. On the return journey it was troublesome on the Sobat 

 and on the AVhite Nile to a little north of Kaka. 



The Seroot is most persistent in its attacks all through the day, 

 but especially late in the afternoon, when it only leaves off in time 

 for the Mosquitoes to come on. The Seroot bites one even through 

 one's shirt and at the knees through cord riding-breeches ; if 

 driven off there is no after effect from the bite, but if allowed to 

 remain biting for long the wound becomes irritable and slightly 

 swollen next day. 



Tab anus sp. inc. 



A second, larger species of Seroot was occasionally met with, 

 with a black abdomen. In size it agrees with Tabanus biyuttatus, 

 but the female has a whitish thorax instead of yellow as in that 

 species, of which I think it may be a variety. 



Mosquitoes. 

 Both going and coming back along the White Nile we met very 

 few Mosquitoes between Omdurman and the Sobat ; on the Zeraf 

 from March 23rd to 25th they were not numerous ; on March 26th 

 in the White Nile they first became troublesome ; and on the 27th 

 in Lake No were a great nuisance, rendering sleep almost impossible 

 except under curtains of extra fine mesh ; though so small, these 

 Mosquitoes are very venomous. On the Ghazal from March 28th to 

 April 1st they swarmed in the papyrus, but in places where there 

 was a break in the swamps there were very few and it was 

 possible to sleep in comfort. On the Bahr-el-Jebel from 3rd to the 

 13th April we never had any peace from them from about sunset 

 till a couple of hours after sunrise. Nowhere in the East have I met 

 Mosquitoes in such numbers, or so venomous and persistent in 

 attacking one : not only the English officers, but also the Egyptian 

 and Soudanese soldiers and Nubian boatmen suffered much from 

 them. 



IX. MILLIPEDES. 



Aechispibostbeptus sp. inc. 



Three specimens G-abt-el-Meghahid, and two near mouth of 

 Zeraf : the only Millipedes met with. 



