172 BULLETIN 85, UNITED STATES NATIONAL MUSEUM. 



Fig. 15. Psylla alni americana, showing frons, clypeus, labrum, labium, etc. 



16. Paurocephala magnifrons, front view of head, showing frons, clypeus, etc. 



17. Apsylla cistellata, corresponding view as in (16), but actually ventral. 



18. Aphalara veaziei, same. 



19. rhacopteron Icntiginosum , same. 



20. Livia coloradensis , same. 



21. Psyllopsis fraxinicola, same, more enlarged. 



Plate 4. 

 [ Lateral and cephalic views of head.] 



22. Livia juncorum, lateral aspect. 



23. Same, cephalic aspect. 



24. L. vernalis, ventral aspect. 



25. L. viaculipennis, cephalic. 



26. L. vernalis, lateral. 



27. L. coloradensis, cephalic. 



28. X. caricis, lateral. 



29. Rhinocola aceris, ventral aspect. 



30. Same, cephalic. 



31. Same, lateral. 



32. Eupyllura ardostaphyli, lateral. 



33. Livia coloradensis, lateral. 



34. Euphyllura arctostaphyli, cephalic. 



35. Eu. pUllyrese, lateral. 



36. Same, cephalic. 



Plate 5. 

 [Views of head.) 



37. Ceriaa-emum setosum, cephalic. 



38. Euphalerus nidifex, cephalic. 



39. E. vermiculosus. 



40. E. nidifex, lateral. 



41. E. vei'miculosus, lateral. 



42. Arytaina genistas, lateral. 



43. Ceriacremum setosum, lateral. 



44. Floria spectahilis, lateral. 



45. F. radiata, lateral. 



46. Psyllopsis mexicana, lateral. 



47. P. fraxinicola, lateral. 



48. P. fraxini, lateral. 



49. Same, cephalic. 



50. Arytaina robusta, lateral. 

 50a. Same, cephalic. 



51. A.fuscipennis, lateral. 



52. A. pubescens. 



53. A. amorphx. 



54. Aphalaroida sucdncta. 



55. A. ericse. 



56. Arytaina robusta. 



57. A. assimilis. 



58. A. ceanothse. 



59. Aphalaroida pithecolobia. 



60. Arytaina minuta. 



