32 



while writing about the proboscis, and he often uses the term inflate (gonfler) in 

 regard to the proboscis or its parts. He writes (p. 259), " The fly can increase 

 the volume of its trunk and can diminish it to a certain extent." * He further 

 writes (p. 260), " One easily compels a fly to show its entire trunk, finely extended 

 and well inflated; one has only to press between the two fingers the thorax, ' 

 either laterally or from above and below ; it seems as if one obliged the fly, 

 immediately, to put out the tongue." ** Reaumur regarded the proboscis of 

 Musca to be composed of, or folded into, two joints. 



GLEICHEN, 2 '' in 1764 (p. 19-21), describes the proboscis of Musca domestica. 

 He regards the proboscis as made up of three parts, longitudinally, namely a 

 basal sac, a middle tube, and the proboscis proper, the latter being only the 

 labellae. He writes (p. 19) that " The extension of the proboscis probably arises 

 from the air, which is driven by the fly into the sac, and from this into the 

 [middle] tube, finally into the lips. The elevation and depression of the proboscis 

 is, however, brought about by the process with which the [middle] tube is sup- 

 ported." *** Gleichen writes further (p. 21), " The fly can indeed, as I have 

 already mentioned, drive air between the membranes of the proboscis into the 

 lips, but cannot take in air with them." f 



Gleichen did not succeed in finding the part now known as hypopharyux in 

 Musca domestica. He regarded the basal sac, or basal part of the proboscis, as 

 a pumping organ. 



GERSTFELDT-S statements 3 (p. 24-26) regarding the mouth-parts of Musca may 

 be noticed briefly as follows : the under lip, according to him, was what will be 

 later described as labrum-epipharynx ; his hypopharynx, as mentioned in the 

 historical notes (p. 7) of this paper, was really the epipharynx, separated 

 by the action of caustic potash, from the labruni ; the real hypopharynx was not 

 discovered by Gerstfeldt; the rudiments of the mandibles appear, according to 

 Gerstfeldt, as the dorsal corner, on each side, of the fulcrum ; the maxillae form 



* "La Mouche peut augmenter le volume cle sa trompe & le diminuer jusqu'a un 

 certain point." 



** " On force aisement une Mouche a montrer sa trompe toute entiere, bien etendue & 

 bien gonflee; on n'a qu'a presser entre deux doigts, soit les deux cotes, soit le dessus & le 

 dessous du corcelet; il semble qu'on oblige sur le champ la Mouche a tirer la langue." 



*** "Das Ausstrecken des Riissels riihret vermuhtlich von der Luft her, die von der 

 Fliege in das Sackchen, und von diesem in die Rb'hre, biss in die Lefze, getrieben wird. 

 Das aufrichten und senken des Riissels aber wird mit dem Hornbeinchen, womit die Ro'hre 

 gefasset ist, bewirket." 



f "Die Fliege kan zwar, wie ich bereits erwahnet, die Luft zwischen den Hauten 

 des Riissels in die Lefzen treiben, aber nicht dainit Luft schb'pfen." 



