Oct. i, i 92 o-Mar. is, w Illustrations xvii 



84. Colletotrichum fructus and C. circinans: A.— Dilution plate from spores of 



Colletotrichum fructus. B— Individual colony of C. fructus on potato 

 agar. C— Apple of Fameuse variety inoculated with mycelium from 

 pure culture of C. circinans. D.— Dilution plate from spores of C. cir- p ag e 

 cinans. E — Individual colony of C. circinans on potato agar 722 



85. Relation of curing conditions to the development of smudge: A, B.— Com- 



parison of onion sets artificially dried immediately after harvest with 

 those not dried. C, D.— Comparison of white onion sets cured in shal- 

 low crates in the field under the best of natural conditions with part of 

 the same lot after exposure to moist conditions for one week 7 22 



Variations in Colletotrichum gloeosporioides 

 Plate 



86. A, B.— Variation occurring in strain 990. The cultures were not made 



from a single spore. C— Variation occurring in a culture of strain 990 

 which was made from a single spore 73 6 



Text Figures 



1. Variability of strains of Colletotrichum gloeosporioides in spore length 728 



2. I, culture 510: A, greenish black mycelium; B, white mycelium. II, cul- 



ture 943: A, black mycelium; B, white mycelium; C, mycelium mostly 

 in medium, growth zoned, abundant spore production. Ill, culture 

 495: A, black mycelium; B, gray mycelium; C, white mycelium. IV, 

 culture 527: A, gray mycelium; B, greenish black mycelium; C, white 

 mycelium; D, black mycelium. V, culture 940: A, greenish black 

 mycelium; B, white mycelium, some greenish concentric circles; C, 

 black mycelium; D, white mycelium; E, white and black mixed 734 



A Transmissible Mosaic Disease op Lettuce 

 Plate 



8 7 . a.— Leaves of Romaine lettuce. B.— Young expanding leaves of head 



lettuce from experiment started March 22 74° 



Leconte's Sawfly, an Enemy of Young Pines 

 Text Figures 



1. Chart showing life and seasonal history of Neodiprion lecontei through the 



active period of three years (November to March omitted, the insect 

 being in the cocoon during this period) 75 1 



2. Position of end of abdomen of female when ovipositing, showing the various 



parts and their position: 1, lance; 2, apical part of sheath; 3, basal part 

 of sheath; 4, nates or ninth tergite; 5, eighth sternite; 6, chitinized rods 

 at base of lancet ; 7, lancet 755 



3. Distribution of Neodiprion lecontei. The larger dots indicate places from 



which specimens have actual^ been received 759 



Plates 



88. Neodiprion lecontei: A.— Adult female. B.— Adult male 7°° 



89. Neodiprion lecontei: A.— Larva. B.— Sixth-stage larva: The muscles of a 



single abdominal segment distributed over several segments to show their 



numbers, position, and attachment 760 



29667°— 21 3 



