ON THE BRITISH SPECIES OF SIMULIUM — II. 231 



Variation. — None noticed, except, as already mentioned, the size of the single 

 dark spot on the head of the larva. 



Blood-sucking. — I have little to add to my previous notes except that up to the 

 time I left Arran (5.vi.l9) I was not attacked, and no females were even seen on the 

 wing in Devonshire (up till 17th June). Probably the insect requires to be on the 

 wing for some time before proceeding to its blood meal. Mr. P. H. Grimshaw writes 

 *' The specimens from Rannoch repeatedly flew at my face, in fact chiefly at my 

 eyelids, and proved very irritating. They did not actually bite, but possibly would 

 have done if I had given them the chance." 



5a. S. reptans var. galeratum, nov. (fig. le). 



Adults. — Not positively identified, but probably identical with S. reptans. 



Larva. — General colour light greenish, with darker but not very conspicuous trans- 

 verse bands on the abdomen. Head yellowish, clypeus with a black spot in the middle 

 of the posterior margin, connected anteriorly with a large roundish black mark which 

 occupies almost the entire breadth of the clypeus ; its edges are not very sharply 

 defined and it has a small anterior emargination, A dark rim above and behind 

 the eye-spots, sometimes entirely surrounding them. Antennae apparently only 

 4- jointed, the first joint longer than the remaining three together, second about 

 equal to the third (the di\dsion between what are usually the first two joints seems to 

 have disappeared). Mentumi as in S. reptans. The pigment-spots within the sides 

 of the sixth and seventh abdominal segments are darker and more conspicuous 

 than usual. No ventral papillae on last abdominal segment. Gills either quite 

 simple or with one or two (rarely three) short branches. Skin round anus with a few 

 minute colourless scales. About 65-70 rows of hooks in the anal sucker, 10-15 

 hooks in each row. 



Pupa. — ^Apparently indistinguishable from that of S. reptans. The respiratory 

 filaments as dissected from the fully developed larva are as in S. reptans, and the 

 single pupa collected that can with certainty be referred to this species (owdng to 

 its stiU retaining the larval head-capsule) showed no obvious difference either in the 

 pupa itself or in the structure of the cocoon from S. reptans. This pupa was 

 unfortunately not isolated, and the adult issuing was lost among a number of 

 S. reptans. 



Material collected. — ^Larvae were abundant on stones and water-plants {Spar- 

 ganium, etc.) in the river Otter at Tipton St. John, S. Devon, 14. vi. 1920, in company 

 with many S. ornatum and >S. reptans, and a few S. equinum and S. aureum. 



Although this species was the most abundant in the larval state, even more so 

 than >S. ornatum, no adults were reared from pupae which could be correlated with 

 these larvae, all the specimens obtained being either S. reptans (in the largest 

 numbers), S. ornatum or S. equinum. This would seem to suggest that the form 

 under consideration may be only a local form of S. reptans which has developed 

 distinct characteristics in the larval state only ; but against this it must be stated that 

 a small number of larvae were obtained at the same time and place which agreed in 

 every respect with the Scotch form of S. reptans as described above. Moreover, 

 in the river Teign, and even in the Sid, two or three miles distant, only normal 



