31 



expenditure of space and a waste of time. I select, therefore, for notice a few 

 of the papers which treat upon the subject of the proboscis of Mutca, or of its 

 mouth-parts, such papers as seem to me to have furnished the more important 

 contributions to our knowledge of the subject, or such papers as have so fully 

 dealt with the subject that they ought not to be overlooked. 



The earliest paper which I have thought worthy of notice here, that 

 deals with the anatomy of the proboscis of Musca, is REAUMUR'S memoir 12 

 upon the trunks, with swollen and fleshy lips, which belong to two-winged 

 flies. * This paper by Reaumur, - - altho published in 1740, over thirty years 

 before Fabricius had reduced the terminology of the oral organs of insects to 

 anything like a system, and over seventy years before Savigny had settled the 

 question that the mouth-parts of insects of all the different orders were homo- 

 logous, - is a very complete and accurate presentation of many anatomical facts 

 in regard to the proboscis of Musca. Reaumur, whose observations in regard to 

 Miis fa were made, for the most part, on M. vomitoria, studied the proboscis, as 

 was his usual method of study, with especial reference to its functions, and to 

 the functions of each of its parts. Reaumur believed the proboscis of Musca to 

 be essentially an organ for sucking, altho he thought that the food was aided, 

 perhaps, by the undulatory motion which he observed in the proboscis, in its 

 passage upward from the mouth, which was, according to him, between the two 

 labellae. By watching a fly rolling a bit of dry sugar between the labellae, 

 gradually moistening it, and thus slowly dissolving it away, Reaumur came to the 

 conclusion that the fly had a salivary secretion, but, altho he describes the 

 hypopharynx, by him termed the spur (aiguillori), as channeled above, he does 

 not seem to have discovered that the channel of the hypopharynx was the 

 outlet for the saliva. Reaumur correctly recognized the labrum-epipharynx as 

 the part of the proboscis through which the food passes, and he therefore termed 

 it the sucker (suqoir'). He called the labellae lips (levres), and writes of them 

 that they are traversed by parallel channels, or flutes (cannelures^), which extend 

 toward the middle of the labellae; but, further on, he incorrectly assumes that 

 this channeling is due to a large number of parallel vessels, which distend with 

 liquid, when one presses the head of a fly, or when a fly wishes to use its 

 labellae. Altho Reaumur does not directly say, in any place, that the proboscis 

 of the fly is extended by means of injecting blood or air into it, yet the idea 

 that the proboscis was extended by inflation was evidently often in his mind, 



: Tome 4, part 1, p. 256-297, pi. 16-18. "Des trompes a levres grosses et charnues 

 des mouches a deux ailes." 



