88 



SMITHSONIAN MISCFXLANEOUS COLLECTIONS VOL. 8l 



Though the homology of the cardo must be left in question, the 

 writer would agree with Borner (1909, 1921) that the part of the 

 maxilla bearing the lacinia, galea, and palpus represents the coxal re- 

 gion of the leg base, and that the basal segment of the palpus is a tro- 

 chanter (fig. 35 A, Tr). The lacinia and galea, then, are coxal endites, 

 and, as Borner proposes, the stipes and palpifcr arc corresponding sec- 

 ondary subdivisions of tJic coxa, or of the coxal region of the maxillary 

 base. In the maxillae and maxillipeds of the Crustacea, Borner 

 claims, the segments bearing the lobes homologous with the insect 

 lacinia and galea are also subdivisions of the coxa. By this interpre- 

 tation, the palpus (fig. 35 A, Pip) becomes the telopodite of the maxil- 

 lary appendage (B) ; its basal union with the stipes or palpifer is the 

 coxo-trochanteral joint (ct), and its principal distal articulation hav- 

 ing a ventral flexure is the femoro-tibial joint (ft). 



Other writers have held somewhat divergent views concerning the 

 homologies of the maxillary segments. Goldi (1913) interpreted the 

 cardo as the coxopodite, the stipes as the basipodite, to which he 

 assigned the lacinia and galea as endite lobes, and the basal segment 

 of the palpus as the ischiopodite. Crampton (1922) gave a modifica- 

 tion of this view in that he proposed that the palpifer represents a 

 segment, the ischiopodite. and that the galea is an endite of this seg- 

 ment. Uzel (1897) appears to give confirmation to this view in his 

 description of the development of the maxilla of Campodea ; the maxil- 

 lary rudiment, he says, is first divided into an outer and an inner lobe, 

 and then the outer lobe splits into two parts, one of which becomes 

 the palpus, the other the galea. If the maxilla of Campodea resembles 

 that of Japyx (fig. 30 A), however, it is easy to believe that the 

 structure in the embryo might be misinterpreted, in as much as the 

 adult structure is misleading until the muscle relations are taken into 

 consideration (fig. 31 D) ; then it is seen that the basal region of the 

 palpus, which is united with the base of the galea, is the true basal 

 segment of the palp, and not the palpifer — clearly a secondary modi- 

 fication. 



It has already been pointed out that the entire lack of muscle con- 

 nections in the palpifer is a condition that disavows the segmental 

 nature of the palpifer region. Crampton's best example among in- 

 sects of a structure corresponding- with his idea of the segmentation 

 of a maxillary appendage is the maxilla of the larva of Sialis (fig. 31 

 C), in which there is a small lobe (o) borne on the apparent first seg- 

 ment of the palpus. This lobe Crampton would identify as the galea, 

 making the supporting segment the palpifer. The muscles (O, Q) in- 

 serted on the base of this segment, however, clearlv demonstrate that it 



