Scent-organs (?) in Female Midges. 3fi7 



abdominal segments, while between segments 7 and 8 there 

 is another pair which is as long as the whole abdomen, each 

 tube being forked near its base, so that there are apparently 

 four long tubes on this segment. The reddish-orange colour 

 of the tubes is in striking contrast to the shining black I 

 of the insect (/'. brachialis is a species much resembling the 

 common P. flavipes, Mg., but with a yellow base to the 

 abdomen, and smoky wings yellow at the base). 



Examples preserved in spirit were submit ted to Dr. H. 

 Eltringham for his opinion as to the nature of the tubes. 

 Although these were unfortunately not fit for thorough 

 microscopic examination, Dr. Eltringham was able to ascertain 

 that the tubes were of a glandular nature and provided with 

 delicate retractor muscles at different parts of their length ; 

 he expressed the opinion that they were most probably scent- 

 producing glands. It is probable that they are connected 

 with pairing, and serve to attract the males — though I did 

 not observe any males fly into the swarm, and searched in 

 vain for them by sweeping in the vicinity. 



After making the above described discovery T examined 

 every species of this group of Hies which I came across, and 

 found that the tubes were by no means confined to P. bra- 

 chialis ; on the contrary, it seems likely that they will be 

 found, when searched for, in all species of Palpomyia and 

 Bezzia and allied genera. Already the evidence available 

 shows that they exist in seven species, with interesting specific 

 modifications. Pal pomyia flavipes, Mg., and P. p.rceusta,Jjw., 

 show a pair of simple (not forked) tubes between segments 7 

 and 8, which, like those of P. brachialis, are as long as the 

 whole abdomen ; these species also have three, or perhaps 

 four, pairs of very short blunt-ended tubes, each hardly longer 

 than one abdominal segment, between tergites 4-7 or 3-7. 

 In P. flavipes the tubes have a similar reddish-orange colour 

 to those of P. bracliialis, but in P. prceusta they are for the 

 most part pale in colour. 



Another (undetermined) species of Palpomyia also 

 shows tubes, the precise form of which was not properly 

 made out. 



A slightly different arrangement is seen in P. distincta, 

 Hal., in which species the four pairs of tubes are all of about 

 equal length (about as long as three segments) and quite 

 colourless. 



In the genus Bezzia I have so far had an opportunity of 

 examining two species. B. annulipes, Mg. {? solstitialis, 

 Winn.), has three pairs of colourless tubes, the pair between 



