82 



A. INGRAM AND J. W. SCOTT MACFIE. 



2. 



Single seta at the posterior angle of the 8th segment 



Tuft on the 8th segment 



Tuft on the 8th segment long, half the length of the paddle or more . . 



Tuft on the 8th segment short, less than half the length of the paddle 



0. domesticus. 

 .. 3 

 .. 4 

 .. 5 



6. 



Paddles with a fringe and a single long terminal seta . 

 Paddles without a fringe, short bifid terminal seta 

 (Paddle plates " run at sharper curve from the ribs ") 

 Paddles of usual shape 

 Paddles with a fringe 

 Paddles without a fringe 



0. apicoannulatus. 



0. simulans. 



0. nigricephalus. 



.. 6 



0. albocephalus. 



0. minutus, 



0. punctothoracis, 



0. caliginosus. 

 This table is given with considerable diffidence, as we have ourselves examined 

 only two of the species. Bacot figures three, namely, 0. simulans, 0. apicoannulatus 

 and 0. minutus, 0. sudanensis was briefly mentioned by us in a previous paper 

 (Bull. Ent. Kes. vii, p. 7), and the others were described by Wesche. 0. albocephalus, 

 Theo., has not previously been described, or figured. 



Ochlerotatus albocephalus, Theo (fig. 5). 



The paddles are oval in shape and show a well marked midrib, a slight external 

 thickening or buttress, a slight but distinct external fringe, and a long terminal seta. 

 The terminal seta is one-fifth the length of the midrib and in this respect resembles 

 that of 0. minutus as figured by Bacot. The 8th segment bears at each posterior 



Fig. 5. Ochlerotatus albocephalus, Theo. 



angle a small tuft of about four simple or pubescent hairs, which is just about the 

 same length as the terminal seta on the paddle, namely, one-fifth the length of the 

 midrib. Internal to the tuft, close to the outer margiruof the paddle there is a long, 

 slender, single or bifid hair. At the posterior angle of the 7th segment there is a 

 bifid seta and a few small hairs, and along the posterior margin of the segment are a 

 number of delicate and rather long hairs. On the 4th, 5th and 6th segments one of 

 the setae on the posterior margin and a little internal to the angle is especially de- 

 veloped, so that it reaches right across the following segment. This seta may be 

 single or double. The dendritic setae on the 1st segment are well developed. On 

 the 2nd segment there is also a pair of dendritic setae, which are, however, much 

 smaller than those on the 1st segment and but poorly chitinised. 



