1922] Otanes: Head and Mouth-Parts of Mecoptera 323 



Fig. 10. Panorpa americana, cephalic aspect of head. 



Fig. 11. Boreus nivoriiindus, cephalic aspect of sinistral mandible. 



Fig. 12. Panorpa americana, caudal aspect of sinistral mandible. 



Fig. 13. Panorpa americana, cephalic aspect of sinistral mandible. 



Fig. 14. Boreus nivoriundns, cephalic aspect of head. 



Fig. 15. Panorpodes carolinensis, cephalic aspect of sinistral mandible. 



Fig. 16. Apterobiltaciis apteriis, caudal aspect of sinistral mandible. 



Fig. 17. Panorpodes oregonensis, caudal aspect of head. 



Fig. 18. Merope tuber, caudal aspect of sinistral mandible. 



Fig. 19. Bittacus strigosus, caudal aspect of head. 



Fig. 20. Panorpodes oregonensis, caudal aspect of sinistral mandible. 



Fig. 21. Panorpodes oregonensis, cephalic aspect of sinistral mandible. 



Fig. 22. A plerobittacus apterus, caudal aspect oi head. 



Fig. 23. Panorpodes carolinensis, caudal aspect of sinistral mandible. 



Plate XXVI. 



Fig. 24. Panorpa americana, caudal aspect of head. 



Fig. 25. Merope tuber, caudal aspect of head. 



Fig. 26. Boreus nivoriundns, caudal aspect of head. 



Fig. 27. Panorpodes oregonensis, lateral aspect of head. 



Fig. 28. Bittacus strigosus, lateral aspect of head. 



Fig. 29. Apterobittacus apterus, lateral aspect of head. 



Fig. 30. Merope tuber, lateral aspect of head. 



Fig. 31. Panorpa americana, lateral aspect of head. 



Fig. 32. Boreus nivoriundns, lateral aspect of head. 



Plate XXVII. 



Fig. 33. Bittacus strigosus, antenna 



Fig. 34. Merope tuber, antenna. 



Fig. 35. Borens nivoriundns, antenna. 



Fig. 36. Boreus nivoriundns, labium and maxillae. 



Fig. 37. Panorpodes oregonensis, ental portion of tentorium. 



Fig. 38. Panorpodes oregonensis, lateral view of tentorium. 



Fig. 39. Panorpodes oregonensis, caudal aspect of tentorium. 



Fig. 40. Bittacus strigosus, lateral view of tentorium. 



Fig. 41. Bittacus strigosus, maxilla. 



Fig. 42. Panorpa americana, cephalic aspect of galea. 



Fig. 43. Bittacus strigosus, cephalic aspect of galea. 



Fig. 44. Apterobittacus apterus, lah'mm and vaaxlWie. 



Fig. 45. Panorpodes carolinensis, labium and maxillae. 



Fig. 46. Merope tuber, labium and maxillae. 



Fig. 47. Panorpa americana, maxilla. 



Fig. 48. Panorpa americana, labium and maxillae. 



Fig. 49. Panorpodes oregonensis, labium and maxillae. 



Plate XXVIII. 



Fig. 50. Panorpodes oregonensis, epipharynx. 



Fig. 51. Panorpa americana, diagrammatic section to show hypopharynx, salivos 

 and salivary duct. 



Fig. 52. Bittacus strigosus, epipharynx, hypopharynx and mandible. 



Fig. 53. Apterobittacus apterus, hypopharynx and salivary duct. 



Fig. 54. Merope tuber, hypopharynx and salivary duct. 



Fig. 55. Merope tuber, lateral view of galea. 



Fig. 56. Panorpa americana, caudal aspect of head, to show mandibles, tendons 

 and postpharynx. 



Fig. 57. Bittacus strigosus, mecaglossa and palpi folded back to show hypo- 

 pharynx and salivos. 



Fig. 58. Panorpodes oregonensis, hypophar3mx and salivary duct. 



Fig. 59. Merope tuber, epipharynx and mandible. 



Fig. 60. Boreus nivoriiindus, hypopharynx. 



Fig. 61. Panorpa americana, epipharynx, hypopharynx, salivos. 



