This is a strictly coastal species that is evidently specific in larval feeding to Ericameria ericoides ... The larvae of ... G. ericameriae cause gall-like deformities of terminal foliage tips. These are small, ca. l cm, onion dome-shaped. hollow 'galls' that appear to consist of leaflets sealed together like the staves of a barrel, rather than typical growth of gall tissue (Fig. 100 [on pg. 45]). The larva skeletonizes within this shelter, and drops to the ground for pupation, leaving thin, partially eaten leaflets, which wither and dry by midsummer. Adults emerge in July and August