PSYCHE. 



365 



glossae, which in Simulium, Rhyphus, 

 Dixa, and even in Syniplecta (a Tipu- 

 lid) are free and distinct, and without 

 sign of pseudo-tracheae. The gradual 

 coalescence of paraglossae is seen 

 plainly in Mycetophila and among the 

 Tipulids, and the gradual appearance 

 of the pseudo-tracheae can be readily 

 traced in the Tipulid family. The gen- 

 eral tendency of specialization of the 

 mouthparts of the Nematocera is toward 

 the reduction and loss of the mandibles 

 and maxillae, and toward the special 

 development of the labium to be a 

 rasping, lapping organ, all-important in 

 food taking. The physiological change 

 in food habit from blood-taking or sap 

 sucking, which demands piercing and 

 elongate sucking parts, to the lapping 

 of exposed liquids or the taking of solid 

 food in small rasped-off particles mixed 

 with a salivary or other secreted fluid, 

 has been accompanied by the general 

 structural change already indicated. 



Now, is the highly specialized mouth 

 of the Muscidae and other similar Bra- 

 chycerous Diptera reducible to the Ne- 

 matocerous mouth ? Can the parts of 

 the mouth of Musca be homologized 

 with the parts of the Nematocerous 

 mouth ? To display the evidence which 

 the comparative anatomy of the mouth- 

 parts presents touching the point will 

 require another paper. It is necessary 

 to present the gradations between the 

 most specialized of the Nematocerous 

 mouths, say that of Tipula, and the 

 mouth of Musca. I may only say here 

 that to any one at all acquainted with 



the Dipterous mouthparts this will not 

 be taken to be a very difficult matter. 



Finally, can the Nematocerous mouth 

 be reduced to the orthopterous, biting 

 type of mouth ? Are the so-called man- 

 dibles, maxillae and labium of Blepha- 

 rocera or Ceratopogon homologous with 

 the mandibles, maxillae and labium of a 

 cockroach ? Unfortunately there is no 

 persistent racial genus of flies with 

 orthopterous mouthparts, like Erioce- 

 phala among the Lepidoptera. The 

 persistence of Eriocephala enables the 

 development of the highly specialized 

 mouth structure of the butterfly to be 

 traced backward through the higher 

 moths, through the Tineids, and finally 

 through Eriocephala directly to the 

 orthopterous type. Comparative anat- 

 omy can here unaided satisfactorily 

 reveal the homologies. 



But with the Diptera the most gen- 

 eralized mouth is far from the orthop- 

 terous type. And yet it seems not 

 unreasonable, nor violently imaginative 

 to see in the mouth of Blepharocera, 

 the modified but still recognizable man- 

 dibulate mouth. However, a study of 

 the development, the ontogeny of the 

 mouthparts of some Nematocerous form 

 is necessary to present the needed con- 

 firmation of this supposition, and this 

 testimony of the ontogeny I hope to 

 present in some future paper. 



As said at the beginning of these 

 notes, the scope of this paper is limited 

 to the study of the comparative anatomy 

 of the mouthparts of the Nematocerous 

 Diptera. 



