Scent-organs (?) in Female Midges. 367 



abflominal sefjments, while between sefrments 7 and 8 tliere 

 is nriotlier pair wliicli is as long as the whole abilonien, each 

 tube beino- forked near its base, so that there are apparently 

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

 of the lubes is in strilcin<>- contrast to the shining black body 

 of the insect (P. hrachialis is a species much resembling the 

 common P. flavipefi, M^-., but wifh a yellow base to the 

 ab lomen, and smoky winijs yellow at the base). 



Examples preserved in spirit were submitted 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. Eltringliam 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- 

 producino- glands. It is probable that they are connected 

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

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

 vain for them by sweej)ing in the vicinity. 



After making the above described discovery I examined 

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

 found that the tubes were by no me;ins confined to P. hra- 

 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 

 modificatic^is. Palpomyia fidvipes, ^Ift"-, and P. prwiista, Lw., 

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

 and 8, wliich, like those of P. hrachiiUs, 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 coliMn* 

 to those of P. hrachialis, but in P. prcedf'tu they arc for the 

 most part pale in colour. 



Another (undetermined) species of Palpomyia also 

 shows tubes, the precise form of wliich 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. (? sols fit ialis, 

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



