ON THE BRITISH SPECIES OP SIMULIUM. 33 



Distribution.— This seems to be the representative in the South of England of the 

 more northerly S. reptans, though it also occurs in Scotland, but apparently rarely. 

 England : New Forest (V.,Y.) ; Christchurch ( Y.) ; Lymington {Dr. L. W. Samhon) ; 

 Enslow, Oxfordshire (H.) ; Cambridge (J., females only) ; Fakenham, Suffolk (iV.,. 

 females only). Scotland : Aviemore {K., the male figured). 



Habits.— QoXoYvd Yerbury notes : " This fly bites and annoys one in the forest.'*^ 



Synonymy. — Although it is possible that one of the older names may apply to this 

 species, it is impossible to be certain, and it therefore seems wisest to propose a new 

 name. The species is referred to (but not named) by Austen in his British Blood- 

 sucking Flies, though an examination of the series on which his remarks were based 

 shows that though all the females are S. morsitans, all but one of the males are 

 S. austeni. 



5. Simulium austeni, sp. n. (fig. 1,/). 



Differs from S. reptans as follows ^-Male legs entirely dark blackish-brown, except 

 for the silvery patch on the front tibiae. Claspers (fig. 1,/) rather longer and of a 

 slightly different shape, and provided near the base on the inner edge with an inwardly 

 projecting thumb-like process (this does not show up well in the figure ; it is best seen 

 in an oblique side-view) ; adminiculum and its appendages practically the same as in 

 S. morsitans. Female (if correctly identified in a single specimen from Barnham) 

 with the pale markings rather less distinct even than in S. morsitans. 



The difference in the form of the male claspers is quite sufficient to distinguish 



5. austeni specifically from S. morsitans. About 8 mounts of the genitalia were 

 compared, and many others examined in the dry state. There was no observable 

 variation. Possibly when more females are discovered better characters can be 

 adduced for the separation of that sex from S. reptans and 8. morsitans. 



Type (J in the British Museum, from Rugby, 23. iv. 1893 {E. E. Austen). 



Time of appearance. — The dates of capture of the specimens examined range only 

 from 23rd April to 22nd May. 



Distribution. — England: West Moors, Dorset {¥.); Rugby (E. E. Austen); 

 Shotover and Lye Hill, Oxford (H.) ; Cambridge (J.) ; Barnham, Suffolk {N.) ; 

 Felden, Herts. (P.). 



Habits. — Austen found the males " dancing in a swarm in the afternoon by a 

 gate in a field." 



Synonymy. — The same remarks apply to this species as to S. morsitans. I at 

 first confused it with S. tuberosum, but the two are really quite distinct. 



6. S. tuberosum, Lndst. (figs. 1, 2, 4). 



Differs from S. reptans as follows : — Male : legs entirely black ; hind metatarsus 

 (fig. 4, 6) considerably more thickened ; no distinct silvery-grey margin to the mesono- 

 tum, though the shoulder- spots are well-marked. Genital claspers (three mounts com- 

 pared ; fig. 1, e) resembhng those of S. austeni, but more slender and slightly widened 

 towards the tip ; the internally projecting thumb-like process near the base well 

 developed, but not so broad as in S. austeni ; adminiculum with its ventral portion 

 very short and broad, its internal appendages smaller and less complicated than in 

 (C155) c 



