24 c Canadian Arctic Expedition, 1913-18 



EXPLANATION OF PLATE III. 



Hypopygium of Nephrotoma arcticola; ninth tergite, dorsal aspect. 



■" N. arcticola; outer pleural appendage. 



" Tipula hewitti; the same. 



" T. besselsoides; the same. 



" T. johanseni; ninth tergite, dofsal aspect. 



" T. diflava; the same. 



" T. d'ij^awa; lateral aspect; 9t. ninth tergite; 9 pZ. ninth pleurite; 



9 s. ninth sternite. 



" Tipula arctica; ninth tergite, dorsal aspect. 



" T. hewitti; the same. 



Hypopygium of T. arctica; inner pleural appendage. 



" T. suhpolaris; ninth tergite, dorsal aspect. 



" T. besselsoides; the same. 



Ovipositor of T. arctica; female sternal valves. 

 Hypopygium of T. subarctica; ninth tergite, dorsal apseot. 



" T. besselsoides; inner pleural appendage. 



Ovipositor of T. arctica; dorSal aspect. 



EXPLANATION OF PLATE IV. 



Fig. 44. Larva of Poecilostola, supposition; spiracular disk. 



45. " Tipula arctica; the same. 



46. " Stygeropis, supposition; the same. 



47. " Tipuline No. 2; dorsal aspect of entire larva. 



48. " Tipuline No. 2; spiracular disk. 



49. " Tipuline No. 3; the same. 



EXPLANATION OF PLATE V. 



Fig. 50. Pupa of Tipula arctica; male, lateral aspect. 



" 51. " T. arctica; female; dorsal aspect. 



" 52. Larva of Tipula arctica; labrum, dorsal aspect. 



" 53. " T arctica; mentum, ventral aspect. , 



" 54. " Poecilostola, supp. ; outer lobe of maxiUa. 



" 55. " Poecilostola, supp.; mandible. 



" 56. " Tipula arctica; chsetotaxy of third abdominal tergite; dorsal aspect. 



" 57. " T. arctica; the same, third abdominal sternite; ventral. 



" 58. " Stygeropis, supp.; the same, third abdominal tergite; dorsal. 



" 59. " Stygeropis, supp.; the same, third abdominal sternite; ventral. 



" 60. " Tipuline No. 1; the same, third tergite; dorsal. 



" 61. " Tipuline No. 1; the same, third sternite; ventral. 



" 62. " Tipuline No, 2; the same, third tergite; dorsal. 



" 63. " Tipuline No. 2; the same, third sternite; ventral. 



" 64. " Tipuline No. 3; the same, third tergite; dorsal. 



" 65. " Tipuline No. 3; the same, third sternite; ventral. 



EXPLANATION OF PLATE VI. 

 Figs. 1, 2. Female of Tipula arctica Curtis (Photos, by Geo. H. Wilkins) 



