Heymons considers that it represents the sternites of the three trophal segments, and that the gula is merely a secondary development.
I and 2, Sternites of the first and second opisthosomatic somites.
2 and 3, Sternites of the second and third somites of the opisthosoma, each showing a tracheal stigma.
to and it, Sternites of the tenth and eleventh somites of the opisthosoma.
The word usage examples above have been gathered from various sources to reflect current and historial usage. They do not represent the opinions of YourDictionary.com.