preliminary remarks on the nature, size, direction, and general form of the 

 proboscis, the author considers the parts and their nomenclature according to 

 previous authors. His compilation of authorities is very complete. In a few 

 words, the author's own views may be condensed as follows : The proboscis of 

 the diptera consists of a sheath and its enclosed setae, or bristles. The sheath 

 is made up, sometimes of the labium alone, sometimes of the labium as the chief 

 portion, together with other mouth-parts; it can be regarded as consisting of 

 three parts, the basis, the stem or stalk, and the end-lobes (labellae of Kirby). 

 The setae or bristles enclosed in the sheath represent the remaining mouth-parts, 

 and are either given as two, four, or six ; or as one, three, or five ; according 

 as whether one includes the labrura with them or not. The labrum is more or 

 less elongated, sometimes with a longitudinal furrow in the middle, supposed by 

 Gerstfeldt to be an indication that this mouth-part was composed originally of 

 lateral halves. The other setae, when they are all present, are the mandibles* 

 maxillae and hypopharynx. Parts of the mandibles or maxillae sometimes unite 

 with the labium to help form the sheath. The hypopharynx, or tongue, is absent 

 in very few diptera. The epipharynx perhaps exists in a few cases, according to 

 Gerstfeldt (p. 21), altho he says he has nowhere seen it. At the basis of the 

 proboscis are regularly, if not invariably, two more or less developed palpi. 

 Following the portions of Gerstfeldt's paper, of which the proceeding is an abstract, 

 is a brief description of the mouth-parts, their mode of coalescence, and their 

 presence or absence, in different families and genera of the diptera, beginning with 

 diptera having two setae and ending with those having six. 



Gerstfeldt's work was based, as is apparent from' his introductory remarks 

 (p. 4-5 ), on the view of Brulle that fill the mouth-parts of insects were reducible 

 to the modification of six pairs of appendages, themselves serial homologs of the 

 thoracic ambulatory appendages. The theory seems to have been assumed at 

 the outset of the author's work, and, therefore, to have had too much influence 

 on the conclusions which Gerstfeldt drew from his othenvise, in general, accurate 

 observations, for Gerstfeldt examined a large variety of material in the preparation 

 of his paper, and examined it carefully, as far as the instruments at the disposal 

 of anatomists of his time would allow. His failure, however, to recognize the 

 epipharynx in diptera led him to make a curious mistake. He has described, as 

 Menzbier 8 correctly observes (p. 65), the epipharynx of Musca freed from the 

 labrum as the hypopharyux, and failed to discover the true hypopharynx. He 

 regarded the longitudinal "suture" (probably in reality the channel) of the 

 epipharynx (his hypopharynx), as an indication that the hypopharynx owes its 

 origin to the coalescence of paired organs. Another mistake which Gerstfeldt 



