XVI 
Journal of Agricultural Research 
Vol. V 
Page 
Plate LXVIII. Embryology of Aphis pomi: Fig. i.—Fertilized egg previous 
to formation of blastoderm. Fig. 2.—Fertilized egg showing formation of 
blastoderm. Fig. 3.—Unfertilized egg. Fig. 4.—Polar organ. Fig. 5.— 
Conditions of embryo and polar organ at commencement of revolution. 
Fig. 6.—Yolk cell. Fig. 7.—Germ cell. 994 
Plate LXIX. Embryology of Aphis pomi: Fig. 1.—Ovarian yolk before divi¬ 
sion. Fig. 2.—Half of ovarian yolk shortly after “dumb-bell’* formation. 994 
Plate LXX. Embryology of Aphis pomi: Fig. 1.—Half of ovarian yolk, end 
chambers forming. Fig. 2.—Half of ovarian yolk, end chambers formed.. 994 
^ Plate LXXI. Embryology of Aphis pomi: Fig. 1.—Half of ovarian yolk, egg 
chambers forming. Fig. 2.—Thickening serosa accompanied by cells of 
polar organ. 994 
Plate LXXII. Embryology of Aphis pomi: Fig. 1.—Invagination of dorsal 
body. Fig. 2.—Dorsal body completely formed. 994 
Plate LXXIII. Embryology of Aphis pomi: Emerging nymph, showing egg 
burster. 994 
Plate LXXIV. Structural details of Aphis pomi, A. avenae, and A. malifoliae: 
Fig. 1.— Aphis pomi: Antenna of wingless viviparous female, adult. Fig. 
2.— A . pomi: Antenna of wingless viviparous female, third instar. Fig. 3.— 
A . pomi: Antenna of wingless viviparous female, second instar. Fig. 4.— 
A. pomi: Antenna of wingless viviparous female, first in$tar. Fig. 5.— 
A. pomi: Antenna of stem mother. Fig. 6.— A. pomi: Antenna of inter¬ 
mediate. Fig. 7.— A. pomi: Antenna of winged viviparous female. Fig. 
8.— A. pomi: Male genitalia. Fig. 9.— A. pomi: Antenna of male. Fig. 
10. — A. pomi: Antenna of wingless viviparous female, fourth instar. Fig. 
11. — A. pomi: Cornicle of winged viviparous female. Fig. 12.— A. pomi: 
Cornicle of wingless viviparous female. Fig. 13.— A. pomi: Cornicle of 
male. Fig. 14.— A. pomi: Cornicle of oviparous female. Fig. 15.— A. 
avenae: Antenna of stem mother, first instar. Fig. 16.— A. pomi: Antenna 
of stem mother, first instar. Fig. 17.— A, malifoliae: Cornicle of winged 
viviparous female. Fig. 18.— A. avenae: Cornicle of winged viviparous 
female. Fig. 19.— A. pomi: Cauda of adult. Fig. 20.— A. pomi: Hind 
tibia of oviparous female. Fig. 21.— A. pomi: Cauda of pupa. 994 
PLATE LXXV. Aphis pomi on its host plant: Fig. 1.—Colonies on apple. Fig. 
2.—Apple twig bearing eggs. 994 
Soilstain, or Scurf, of the Sweet Potato 
Plate LXXVI. Fig. 1.—Petri dish containing a pure culture of Monilochaetes 
infuscans. Fig. 2.— a , Part of a conidiophore of M. infuscans, showing the 
unbroken chain of conidia; b, d , and k , various ways of the breaking up of 
the chains of conidia when disturbed or moistened; c, e , /, g, h , and j, 
spores collecting in pockets after the chains of conidia have broken up; i, 
bending in of the chain of conidia prior to breaking up into individual 
spores... 1002 
Plate LXXVI I. a , Part of a cross section of a sweet-potato root, showing the 
relationship of Monilochaetes infuscans to the epidermis of the host; 6, 
germination of a fragment of mycelium of M. infuscans, showing the germ 
tube which is first produced and upon which conidia are borne; c, d, e, /, 
g, h, i, and t, different stages in the development of the spore and the 
chain of conidia; 0, j, k, and p, protruding hyaline tube at the tip of the 
conidiophore on which are borne the conidia; l, n, and w, differentiation 
of the coarser dark mycelium, and the finer hyaline to subhyaline hyphae; 
u, attachment of the conidiophore to the mycelium; r, conidiophore-bear- 
ing mycelium, being part of u; m , q, s , v, x, y, and z , different stages in the 
germination of the conidia of M. infuscans . 1002 
