Bull. U. S. F. C. 1899, (To face page 104.) 
Plate 17. 
Fig. 15. Mastigocerca bicornis Ehr. Side view. (X 285.) Fig 18. Mastigocerca mucosa. Side view, showing the furrow 
Fig. 16. Mastigocerca elongata Gosse. Side view. (X 285.) between two dorsal ridges. (X 490.) 
Fig. 17. Mastigocerca bicristata Gosse. Side view of lorica, show- 
ing the two ridges. (X 490. ) 
