HANSEN, H. J.: HEMIMERUS TALPOIDES WLK. 87 



■maxillae and maxillipeds in Malacostracous Crustaceans and Insects. 

 Here 1 perhaps may add a note which is the consequence of 

 different paragraphs of the treatise, but is not pronounced ex- 

 pressly: that the mandible, »corpus mandibulse», (the joints of the 

 palpus not included) in the Phyllopoda and other Entomostraca 

 is homotypous zvith iJie basal joint in the limbs of Phyllopoda, 

 the mandible in the Malacostraca is homologous with the man- 

 dible in Phyllopoda and hymotypous with the basal joint in the 

 maxillulœ and maxillce (the »lacinia mobilis» on the mandible 

 being a secondary lobe of the same nature as the lobes from 

 the joints of the maxillse), and the mandible in the Insects is 

 Jw7fiologous with the mandible of the Crustacea (hymotypous 

 with the cardo in the maxillae of Insects but not with the tro- 

 chantin of the legs), conscquejitly consisting of but one joint and 

 no basal joint or joints of it being included in the lateral parts 

 of the head, as set forth by different authors. 



VI. The systematic position of Hemimerus. 



The Hemimerus must be referred either to OrtJioptera or 

 to Thysanura; other Insects-orders being quite out of the question. 

 As stated by Saussure it stands far from the Thysattura con- 

 cerning the structure of the tarsi and in the absence of the ster- 

 nite of the ist abdominal segment; I can add that the structure 

 of the abdomen in the female (two of the segments being reduced 

 and concealed), the short coxae and especially the structure of 

 the mouth removes it very far from the Pliysaimra and leads it 

 to the OrtJioptera. In the Thysanura the mandibles exhibite a 

 shape and an articulation, agreeing even up to details with that 

 which is found f. inst. in the Cumacea: the articulation with the head 

 is stretching very long forward on the inner side of the mandible, 

 and a great part of the muscles issues from the inner wall of the 

 cavity of the mandible and fixes itself with the other end upon 

 a horizontal chitinous plate between the mandibles etc., while in 

 Hemimerus as in the different families of Orthoptcra we find 

 the mandibles articulated with their broad basal end, which is cut 

 almost transversely oft', and being moved about an axis going 

 from a more strongly developed inferior and a rather feeble 



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