PLATE XIII. 



Heterochceta spinifrons, Claus. 



Fig. 1. Female, seen from above, magnified 20 diameters. 



Fig. 2. Anterior antenna of female. 



Fig. 3. Left anterior antenna of male. 



Fig. 4. Posterior antenna. 



Fig. 5. Mandible and palp. 



Fig. 6. Maxilla. 



Fig. 7. Anterior foot-jaw. 



Fig. 8. Posterior foot-jaw. 



Fig. 9. Outer branch of third swimming foot. 



Fig. 1 0. Fifth pair of feet of male. 



Fig. 11. Fifth pair of feet of female. 



Fig. 12. Abdomen of female, with spermatophore attached. 



Fig. 13. Portion of speimatophore, with spermatozoids, more highly magnified. 



