260 PROCEEDINGS OF THE ACADEMY OF [Feb., 



Explanation of Plate XII. 



Fig. 1. — Leptothorax muscorum Nylander. Switzerland. In this and the fol- 

 lowing figures only the profile view of thorax and pedicel (petiole 

 and postpetiole) of the worker are represented. All the figures are 

 from camera lucida drawings. 



Fig. 2. — L. muscorum var. sordidus var. nov. 



Fig. 3. — L. acervorum Mayr. Switzerland. 



Fig. 4. — L. acervorum subsp. Canadensis Provancher. 



Fig. 5. — L. acervorum subsp. Canadensis var. Yankee Emery 



Fig. 6. — L. Emersoni Wlieeler. 



Fig. 7. — L. Schaumi Roger. 



Fig. 8. — L. fortinodis Mayr. 



Fig. 9. — L. longispinosus Roger. 



Fig. 10. — L. curvispinosus Mayr. • 



Fig. 11. — L. curvispinosus subsp. ambiguus Emery. 



Fig. 12. — L. curvispinosus subsp. rugatulus Emery. 



Fig. 13. — L. curvispinosus subsp. annectens subsp. nov. 



Fig. 14. — L. Schmittii sp. nov. 



Fig. 15. — L. nitens Emery. 



Fig. 16. — L. texanus sp. nov. 



Fig. 17. — L. fricarinatus Emery. (After Emery.) 



Fig. 18. — L. neomexicanus sp. nov. 



Fig 19. — L. obturator sp. nov. 



Fig. 20. — L. nevadensis sp. nov. 



Fig. 21. — L. terrigena sp. nov. 



Fig. 22. — L. Andrei Emery. (After Emery.) 



Fig. 23. — L. (Dichothorax) Pergandei Emery. 23a node of petiole seen from 

 behind. 



Fig, 24. — L. {Dichothorax) floridanus Emery. 24a node of petiole seen from 

 beh'nd. 



