24 c 
Canadian Arctic Expedition, 1913-18 
EXPLANATION OF PLATE IIL 
Fig. 28. Hypopygium of Nephroloma arcticola; ninth tergite, dorsal aspect. 
" 29. " A'^. arcticola; outer pleural appendage. 
" 30. " Tipula hewitti; the same. 
" 3L " T. besselsoides; the same. 
" 32. " T. johanseni; ninth tergite, dorsal aspect. 
" 33. " T. difiava; the same. 
" 34. " T. df^afa; lateral aspect; 9 t. ninth tergite; 9 pi. ninth pleurite; 
9 s. ninth sternite. 
" 35. " Tipida arctica; ninth tergite, dorsal aspect. 
" 36. " T. hewitti; the same. 
Fig. 37. Hypopygium of T. arctica; inner pleural appendage. 
" 3S. " T. subpolaris; ninth tergite, dorsal aspect. 
" 39. " T. besselsoides; the same. 
" 40. Ovipositor of T. arctica; female sternal valves. 
" 41. Hypopygium of T. subarctica; ninth tergite, dorsal apsect. 
" 42. " T. besselsoides; inner pleural appendage. 
" 43. Ovipositor of T. arctica; dorsal aspect. 
EXPLANATION OF PLATE IV. 
Fig. 44. Larva of Paecilostola, supposition; spiracular disk. 
" 45. " Tipida 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; labrimi, dorsal aspect. 
" 53. " T arctica; mentum, ventral aspect. 
" 54. " PocdZosio/a, supp.; outer lobe of maxilla. 
" 55. " Poecilostola, supp.; mandible. 
" 56. " Tipida 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. " Tipidine No. 3; the same, third sternite; ventral. 
EXPLANATION OF PLATE VI. 
Figs. 1, 2. Female of Tipida arctica Curtis (Photos, by Geo. H. Wilkins) 
