Eggs of two species belonging to the Arribalzagia Series of the
Laticorn Section of Anopheles (Anopheles) collected in Brazil are
described from scanning electron micrographs. The An. fluminensis
egg is long with shallow floats displaced far dorsally. The narrow deck
region is overlain by a frill modified into prominent ridges that are
nearly continuous to both ends of the egg. Slightly opened decks at both
poles contain an average of four lobed tubercles. Polygonal, plastron-type
chorionic cells cover the lateral and dorsal surfaces. The egg of An.
shannoni is unique in possessing 22-27 fingerlike filaments that project
with regular spacing from each of its massive floats. These filaments and
their bases are highly perforated and are believed to trap air and support
flotation of the egg with the dorsal surface up, contrary to the usual
orientation for anophelines. The eggs are compared with those of related
species bearing similar structures, notably An. fluminensis with An.
mediopunctatus s.s and An. shannoni with An. peryassui.
