diptera have two maxillary palpi aiid have no labial palpi. When the maxillae 

 .are apparently absent, as in the flies properly speaking, they coalesce with the 

 under lip. The mandibles are found only in certain genera ; they are, for example, 

 very evident in the breeze -flies, where they have the form of two slender blades. 

 The hypopharynx and epipharynx are the bristle, or the two intervening bristles. 

 The upper lip is a bristle or broader scale which covers the others." * 



'Saviguy did not stop with the reduction of the mouth-parts of all insects 

 to a common plan, a result which seemed fairly to complete the work begun by 

 Fabricius, but, in his second memoir, recognizing the resemblance between the 

 mouth-parts of hexapods and those of the remaining arthropods (which he terms 

 apiropods), and the graduated forms between the locomotory and manducatory 

 appendages of some of these apiropods, he concludes (p. 43) that, "among these 

 last apiropods [by which he means Limulus, A pus, etc.] the organs which serve 

 for manducation do not essentially differ from those which, among the first 

 apiropods [meaning lulus, Scolopendra, and the like], and among the hexapods, 

 serve for locomotion." ** Here was a direct homologizing of the mouth-parts of 

 insects with locomotory organs, a theory which Saviguy had publicly advanced 

 as early as October 1814. *** The comparison of the paired appendages of 

 spiders, scoloperidra, and Crustacea, which follows (p. 43-60 and 83-101) in his 

 memoir, has little interest in connection with the study of diptera. 



After Savigny had thus led the way, by his theories that all mouth-parts 

 of insects were modifications of the same general plan, and that the paired mouth- 

 parts were serial homologs of legs, little was left in the way of general theories 



: "Voilii done la bouche jdes Hymenopteres composee de quatre organes impaires. 

 sans y comprendre la ganache ou le menton; savoir: la levre superieure, 1'epipharynx, 

 1'hypopliarynx et la levre inferieure, et de deux organes paires, les mandibules et les 

 maehoires. Les memes organes se retrouvent tous, soit separement, soit simultanement, dans 

 la bouche des Dipteres. La levre inferieure existe presque toujours; elle constitue la trompe 

 proprement dite. Les maehoires existe'nt de meme presque toujours: ce sont elles qui 

 portent les palpes, de sorte que les Dipteres ont deux palpes maxillaires, et n'ont point de 

 palpes labiaux. Quand les maehoires semblent disparaitre, comme dans les Mouches pro- 

 prement dites, c'est qu'elles se confondent avec la levre inferieure. Les mandibules ne 

 s'observent que dans quelques genres: elles sont, par exemple, tres- visible dans les Taons, 

 ou elles ont la forme de deux lames tres-deliees. L'hypopharynx et 1'epipharynx sont la 

 soie, ou les deux soies intermediates. La levre superieure est une. soie ou ecaille plus large 

 j]ui couvre les autres." 



* Chez ces derniers Apiropodes, les organes qui servent a la manducation ne dif- 

 ferent pas essentiellement de ceux qui, chez les premiers Apiropodes et chez les Hexapodes, 

 servent a la locomotion." 



*** See foot-note of p. 43 of Savigny's second memoir. 



