278
G E R H A R D K R A U S E A N D K L A U S S A N D E R
Age 10 h (22°C)
17 h
40 h
49 h
4 h (24°C)
12 h
16 h
31 h
FIG. 5. Correlation of centres in coleopteran eggs (adapted from Krause, 1961).
a i -a 4 = Tenebrio (after Ewest, 1937). Germ disc ooplasmically preformed near the
posterior pole (stippled) expands forward ventrally (arrow in a 2 ); primitive groove
appears near posterior pole and expands anteriorly (arrow in a 3 ). Due to these movements
the DC of the germ band (a 4 ), although probably preformed between CC and AC, appears
in front of the CC. b 1 _ i =Melasoma populi L. (after Seidler, 1940, and original). Periplasm moves during cleavage (arrows in b x ); spheroid of cleavage energids is indented at
anterior pole (b 2 ). Germ layers begin to segregate near the middle of the egg (DC, b 3 ).
Germ band expands in both anterior and posterior direction (b 4 ).
c 1 _ i =Leptinotarsa
(after Haget, 1953; and Spohn, unpublished). CC predisposed in ooplasm at or in front of
the middle of the egg (c x ). Defective germ bands resulting from removal of poles during
early cleavage or 512-nuclei stage (c 2 ) indicate limited regulating capacity which is lost
until blastoderm stage (c 3 , complementary germ band parts after section at the 50%
level). DC is initial region of metameric blastema segregation (c 4 ). For abbreviations see
Fig. 3.
G E R H A R D K R A U S E A N D K L A U S S A N D E R
Age 10 h (22°C)
17 h
40 h
49 h
4 h (24°C)
12 h
16 h
31 h
FIG. 5. Correlation of centres in coleopteran eggs (adapted from Krause, 1961).
a i -a 4 = Tenebrio (after Ewest, 1937). Germ disc ooplasmically preformed near the
posterior pole (stippled) expands forward ventrally (arrow in a 2 ); primitive groove
appears near posterior pole and expands anteriorly (arrow in a 3 ). Due to these movements
the DC of the germ band (a 4 ), although probably preformed between CC and AC, appears
in front of the CC. b 1 _ i =Melasoma populi L. (after Seidler, 1940, and original). Periplasm moves during cleavage (arrows in b x ); spheroid of cleavage energids is indented at
anterior pole (b 2 ). Germ layers begin to segregate near the middle of the egg (DC, b 3 ).
Germ band expands in both anterior and posterior direction (b 4 ).
c 1 _ i =Leptinotarsa
(after Haget, 1953; and Spohn, unpublished). CC predisposed in ooplasm at or in front of
the middle of the egg (c x ). Defective germ bands resulting from removal of poles during
early cleavage or 512-nuclei stage (c 2 ) indicate limited regulating capacity which is lost
until blastoderm stage (c 3 , complementary germ band parts after section at the 50%
level). DC is initial region of metameric blastema segregation (c 4 ). For abbreviations see
Fig. 3.