154 



HAROLD HEATH AND BLAKE C. WILBUR. 



PLATE II. 

 Explanation of Figures. 



Successive stages in the development of the soldier caste in a young 

 colony of Termopsis angusticollis. 



FIG 7. Recently hatched young; head width 0.72 mm. 



FIG. 8. Second instar; head width i.o mm. 



FIG. 9. Third instar; head width 1.24 mm. 



FIG. 10. Fourth instar; head width 1.79 mm. 



FIG. n. Fifth instar; head width 2.6 mm. 



FIG. 12. Fully developed soldier; head width 2.97 mm. 



