I) - 



they concern insects with sucking mouth-parts, because that, up to his time, 

 and indeed up to the present time, no sufficiently careful work has been done 

 on these parts to warrant such general conclusions as he pronounces. 



The next important paper, in chronological order, upon the mouth-parts of 

 insects was by BRULLE, 7 in 1844. I have not seen this paper, but I am able 

 to give a brief resume of the author's views, from the reviews of his paper 

 which appear in the dissertation by Gerstfeldt 3 (p. 5-9), in a paper by Menzbier s 

 (p. 18-19), and in Erichson's Bericht iiler die wissenschaftlicJien Leistungen im 

 Gebiete der Entomologie (1844, p. 3-4). Savigny had regarded the labrum, 

 epipharynx, and hypopharynx, as unpaired organs. Brulle sought to include these 

 three organs in the system of paired appendages, which Savigny had established 

 for the mandibles, maxillae and labium. Brulle considered the insect's head as 

 made up of six segments, each with a pair of appendages, or with an unpaired 

 appendage which owed its origin to the coalescence of a pair of appendages. The 

 first segment consequently bore the labrum, the second the epipharynx, the third 

 the hypopharynx, the fourth the mandibles, the fifth the maxillae, and the sixth 

 the labium. 



BLANCHARD, 9 in 1850, considered that the most important modifications of 

 the mouth -parts of diptera were caused by coalescence of parts, and endeavored 

 to support his views by the origin of the nerves which go to these parts. In 

 the Asi/idae, where only four setae are present, he regarded the mandibles as 

 present, but grown together to form what is now termed the hypopharynx. In 

 the Museidae. and in other diptera with two setae, the mandibles were united 

 to form the hypopharynx, and the maxillae coalesced with the labium. The 

 above-expressed view that the so-called hypopharynx is composed of two mandibles 

 grown together, a theory followed in Cuvier's Regne Animal, does not seem so 

 improbable as it otherwise would in the light of Weismann's 10 statement (p. 190) 

 that, in the Muscidae "The mandibular seta arises by coalescence of paired pieces, 

 which surround, like the two halves of a sheath, a cylindrical chain of cells which 

 tapers anteriorly. The cell-chain becomes the salivary duct, which in the imago 

 comes -from behind to the under surface of the seta, so as to unite with it and 

 to open out a little behind its point with a fine opening." * 



GERSTFELDT, S in 1853, (p. 13-47) discusses the mouth-parts of diptera. After 



* " Die Kieferborste entsteht durch Verwachsung paariger Stiicke, welche einen cylin- 

 drischen, nach vorn sich verjiingenden Zellenstrang umschliessen, wie die zwei Halften eines 

 Futterals. Der Strang wird zum Ausfxihrungsgang der Speicheldriisen, der in der Imago 

 von hinten her an die untere Flache der Borste tritt, um mit ihr zu verwachsen und etwas 

 vor der Spitze mit feiner Oeffnung auszumiinden." 



