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Species of the aphid tribe Cerataphidini (Hormaphidinae) form galls of various shapes onStyraxtrees, their primary host, throughout East and Southeast Asia including tropical rainforests. All known species of the tribe produce second-instar sterile soldiers on the primary host and some also produce first-instar sterile soldiers on the secondary host. Here, we review their complicated life cycles with or without host alternation, the formation process of their remarkable galls (flower-like multiple-cavity galls in particular), and all morphs including soldiers. The life cycles of cerataphidines are basically the same as those of the subfamily Eriosomatinae, but in tropical and subtropical regions their life cycles are not very rigidly tuned to seasonal changes in the climate if any. In addition, cerataphidine galls in these regions last at least several months, or at times even for over one year; thus it often takes longer than one year to complete their life cycles.

Insect galls are vulnerable to invasion by moth larvae that can tunnel into the wall. We report that nymphs of the aphid Nipponaphis monzeni repair their gall self-sacrificingly. When a hole was bored into their gall, many globular nymphs discharged a large amount of body fluid from their cornicles onto the gall's wound, and kneaded the fluid, which soon became viscous and eventually congealed, plastering over the hole. Having discharged the fluid, the nymphs shrivelled to approximately one-third of their original volume. Several nymphs were buried in the plaster, like 'aphid sacrifices'. This is the most elaborate social behaviour so far known among aphids.

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Abstract-A non-migratory aphid, Pemphigus spyrothecae, produces l st-instar larvae of 2 types in the gall: thick-legged ones and normal-legged ones. It was found that the thick-legged larvae play a defensive role, hence they may be called soldiers. Unlike the soldiers of other species hitherto reported, at least some soldiers of this species molt and become adults. Their incomplete sterility is explained historically:1) The migratory ancestor of P. spyrothecae once produced monomorphic l st-instar larvae attacking predators in the gall. 2) It acquired a non-migratory life cycle by the larviposition of emigrants in the gall. 3) As a result, lst-instar larvae of another morph, which had lived on the secondary host without attacking predators, joined the gall inhabitants. This hypothesis is supported strongly by the fact that the normal-legged lst-instar larvae very much resemble the lst-instar larvae of migratory Pemphigus species produced on the secondary hosts.