122 Wisconsin Academy of Sciences, Arts, and Letters. 
EXPLANATION OF PLATE VIII. 
Fig. 9. Dissection of nervous system and Gland of Gilson, G. 1-9, ab¬ 
dominal segments. I-VIII, abdominal ganglia. X 4. 
Fig. 10. Gland of Gilson, showing connection with external hollow 
spine. X 43. 
Fig. 11. Diagram showing number and position of the external res¬ 
piratory filaments on one side of body. V., ventral half of seg¬ 
ment. 1. and 2., first and last segments of abdomen. 
Fig. 12. Dissection from dorsal side showing spinning glands. C., 
conducting portion. S., secreting portion. P., union of conduct¬ 
ing portions in press. X 4. 
Fig. 13. Diagram showing shape and relation of cells of spinning 
glands when split along one side and spread out. 
Fig. 14. Two small cells, showing simple nuclei, from the small an¬ 
terior end of the secreting portion. X 160. 
Figs. 15 and 16, More complex nuclei in larger cells taken anterior or 
posterior to the widest part of the secreting portion. X 80. 
Fig. 17. Still more complex nucleus. Note pieces X, Y, attached by 
long slender threads to main nucleus. X 80. 
Figs. 18 and 19. Complex nuclei filling larger proportion of cell than 
the preceding. Some apparent anastomoses could not be satisfac¬ 
torily determined. X 80. 
Fig. 20. Complex nucleus showing many pieces attached by slender 
threads. Many of the apparent anastomoses in this nucleus are 
undoubtedly not real. X 80. 
Fig. 21. Larval case of P. designatus, approaching time of pupation, 
shown by larger stones on anterior end. X 3. 
Fig. 22. Posterior end of same, showing how the border of the case is 
turned in. X 3. 
