ancestral stem at an early period, before the existing forms of
Diptera became so extremely specialized, it seems better to regard the
fleas as constituting an independent order (see FLEA). (E. E. A.)

DIPTERAL (Gr. for "double-winged"), the architectural term applied to
those temples which have a double range of columns in the peristyle, as
in the temple of Diana at Ephesus.

DIPTYCH (Gr. [Greek: diptychos], two-folding), (1) A tablet made with a
hinge to open and shut, used in the Roman empire for letters (especially
love-letters), and official tokens of the commencement of a consul's,
praetor's or aedile's term of office. The latter variety of diptych was
inscribed with the magistrate's name and bore his portrait, and was
issued to his friends and the public generally. They were made of
boxwood or maple. More costly examples were in cedar, ivory (q.v.),
silver or sometimes gold. They were often sent as New Year gifts.

(2)In the primitive church when the worshippers brought their own
offerings of bread and wine, from which were taken the Communion
elements, the names of the contributors were recorded on diptychs and
read aloud. To these names were early added those of deceased members of
the community whom it was desired to commemorate. This custom rapidly
developed into a kind of commemoration of saints and benefactors, living
and dead; especially, in each church, were the names of those who had
been its bishops recorded. The custom was maintained until the lists
became so long that it was impossible to read them through, and the
observance in this form had to be abandoned. The insertion of a name on
the diptych, thereby securing the prayers of the church, was a privilege
from which a person could be excluded on account of suspicion of heresy
or by the intrigues of enemies. His name could, if written, be expunged
under similar circumstances. The names thus written were read from the
ambo, in which the diptych was kept. The reading of these names during
the canon of the mass gave rise to the term _canonization_. By various
councils it was ordained that the name of the pope should always be
inserted in the diptych list.

The addition of _dates_ resulted from the custom of recording baptisms
and deaths; and thus the diptych developed into a calendar and formed
the germ of the elaborate system of festologies, martyrologies and
calendars which developed in the church.

The diptych went by various nam