il ' ii - Northern Research Station - USDA Forest Service

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Figures 3-6.----_alls ofStamnophora vemoniicola on various Vemonia spp. (actual diameter in parenthesis). Figure 3.
On flowerhead ofV. hymenolepis; the left gall (15ram) showing the common opening at the tip. Figure 4. Same,
dissected sagitally (22mm). Figure 5. On stem ofV. lasiopus (40ram). Figure 6. Same, dissected sagitally (45ram).
EVOLUTIONARY CONCLUSIONS Other Tephritinae might have undergone a somewhat
different route, which did not involve flowerhead gallis,
The new findings presented here shed some light on the but a direct transition instead from ungalled flowerl_ads
possible evolution of tephritid galls, especially myopitine to galled stems. This is so hypothesized because
Tephritinae (fig.. 10). The hypothesis of the evolutionary flowerhead galls are practically unknown or nearly so in
transition from development in flowerheads to develop- the other tribes of Tephritinae, most notably in the
ment in stems (Freidberg 1984) is now supported by the Tephritini, Ditrycini and Eutretini, which contain the
following three facts: great majority of gall inducing species in the family.
*** Urophora cardui, which is truely congeneric with
many additional species, galls stems, whereas all ACKNOWLEDGMNETS
other congeners gall flowerheads.
***Stamnophora vernoniicola galls both stems and I am grateful to Amikam Shoob for the photographs, and
flowerheads, to Netta Dorchin and Tuvit Simon for discussions and
***Other species of Stamnophora gall either stems or technical assistance.
' flowerheads.