PLATE 5. 



Fig. 1. Lateral view of prothorax of Ptyelus nymph (Homoptera). 



Fig. 2. Lateral view of mesothorax of Ephemerid nymph. 



Fig. 3. Ventral view of prothorax of Dytiscus larva (Coleoptera). 



Fig. 4. Ventral view of prothorax of Corydalis larva (Neuroptera). 



Fig. 5. Ventral view of prothorax of Hydrophilus larva (Coleoptera). 



P^ig. 6. Ventral view of prothorax and mesothorax of Raphidia larva 

 (Neuroptera). 



Fig. 7. Ventral view of prothorax and mesothorax of Pyrochroa larva 

 (Coleoptera). 



Fig. 8. Ventral view of prothorax of Adela larva (Lepidoptera) based 

 on figure by Forbes, 1910. 



Fig. 9. Ventral view of prothorax of Trichopteron larva. 



PLATE 6. 



Fig. 10. Lateral view of mesothorax of Melanoplus nytnph (Orthop- 

 tera) . 



Fig. 11. Lateral view of mesothorax of Libellulid nymph (Odonata). 



Fig. 12. Ventral view of mesothorax of Eosentomon (Protura), pleural 

 and sternal sclerites spread out as though in one plane. Based on figure 

 by Prell, 1913. 



Fig. 13. Lateral view of mesothorax of Arixenia (Euplexoptera). 



Fig. 14. Ventral view of prothorax of Capnia (Plecoptera), sclerite 

 of pleural and sternal region drawn as though spread out in one plane. 



Fig. 15. Lateral view of mesothorax of Perla nymph (Plecoptera). 



Fig. 16. Ventral view of prothorax and mesothorax of Tenthredinid 

 larva. 



PLATE 7. 



Fig. 17. Lateral view of prothorax and mesothorax of Pteronidea larva 

 (Tenthredinid). 



Fig. 18. Lateral view of mesothorax of Corydalis larva (Neuroptera). 



Fig. 19. Lateral view of prothorax and mesothorax of Trichopteron 

 larva. 



Fig. 20. Lateral view of prothorax and mesothorax of Porthetria larva 

 (Lepidoptera). 



Fig. 21. Lateral view of mesothorax of Calosoma larva (Coleoptera). 



Fig. 22. Lateral view of prothorax and mesothorax of Scarabaeid larva 

 (Coleoptera). 



Fig. 23. Lateral view of prothorax and mesothorax of Panorpa larva 

 (Mecoptera). 



Fig. 24. Lateral view of prothorax of Perla nymph (Plecoptera). 



Fig. 25. Lateral view of prothorax of Echinosoma (Euplexoptera). 



In all figures the coxae have been represented as though par- 

 tially cut off. In all ventral views, the anterior end is directed 

 toward the top of the page; in all lateral views, it is directed 

 toward the right hand margin. 



62 



