PLATE X. 



FIG. I. Posterior end of the body of a larva of C. coloradensis showing the devel- 

 oping caudal appendages. X I1[ 9' At this stage the body mass was unsegmented 

 and the first and second antennae and mandibular legs alone could be distinguished. 



FIGS. 2-6. Developing caudal appendages of B. coloradensis. 



FIG. 2. At the time when six body segments can be seen. X JI 9- 



FIG. 3. At the time when twelve body segments can be seen. X II 9- 



FIG. 4. At the time when all abdominal segments can be distinguished. < 119. 



FIG. 5. Later stage. ( 35. 



FIG. 6. A still later stage. X 35- 



FIG. 7. Male second antenna or clasper of B. Linda hli ; ta, toothed area. X 2O - 



FIG. 8. Male second antenna or clasper of B. coloradensis; t, tubercle; fa, 

 toothed area. ( 20. 



FIG. 9. Distal end of the male second antenna of B. Lindahli viewed from the 

 front. X 35- 



FIG. 10. The same viewed from the outside. x( 35. 



FIG. II. The same viewed from the front and below. ' 35. 



FIG. 12. Distal end of the male second antenna of B. coloradensis viewed from 

 the outside. -X 35- 



FIG. 13. Eye of the female of B. Lindahli, dorsal view ; a, anterior side ; /, pos- 

 terior side. < 35. 



FIG. 14. Eye of the male of B. Lindahli, dorsal view ; a, anterior side ; /, pos- 

 terior side. X 35- 



FIG. 15. Eye of the female of B. coloradensis, dorsal view ; a, anterior side ; /, 

 posterior side. < 35. 



FIG. 16. Eye of the male of B. coloradensis, dorsal view ; a, anterior side ; /, 

 posterior side. X 35- 



260 



