NO. 10 MORPHOLOGY OF GNATHOTRICHUS — SCHEDL 2/ 



Cardo. — The cardo (C) is similar in shape in all three species and 

 is articulated with the ventral angles of the postgena in such a way 

 that the maxilla can be moved laterally as well as in a dorsal-ventral 

 plane. The longitudinal axis of the cardo and that of the stipes (b) 

 enclose an angle of about ninety degrees or even a little less. The 

 articulation of the stipes and the cardo is similar to that of other 

 genera of the family. There is also an articulation between the sub- 

 galea and the cardo. In figure 12, which illustrates this fact, the 

 cardo and the rest of the maxilla are stretched to show the connection. 

 The inner side of the cardo is smooth ; the outer side shows from five 

 to seven hairs which may be called the cardol setae (m). 



Stipes. — On the outer side the stipes is defined as an elongate, sub- 

 parallel sclerite ; on the inner side it is fused with the lacinia. The 



Fig. 12. — Gnathotrichns matcriarius Fitch. ; Maxilla, stretched, the subgalea 



showing. 



setae are not very numerous, about six to eight being present. These 

 are more concentrated anteriorly near the base and near the apex. The 

 latter, situated on the apical area of the stipes, may correspond to 

 the palpiferal setae of some authors. The palpifer (c) being a topo- 

 graphical area of the stipes only, is not limited by lines or sutures. 



Lacinia and galea. — The lobus internus or the lacinia and the lohus 

 externus or the galea are largely fused to form a single large lobe. 

 Apically they are distinctly separated by a moderately deep emargina- 

 tion (i) or notch. The inner free lobe is distinctly larger than the 

 outer one. Posteriorly they are fused. It will need much further 

 investigation to decide the exact areas of these two lobes. In the 

 meantime it is proposed to call the inner lobe and the inner surface 

 of the combined lobes the lacinia and the outer free lobe and the 

 outer surface of the fused part the galea. 



