▁being ▁considered ▁for ▁release ▁in ▁the ▁United ▁States , ▁as ▁existing ▁bi ological ▁control ▁agents ▁have ▁not ▁yet ▁controlled ▁invas ive ▁water ▁hy ac inth . ▁ ▁References ▁ ▁Category : H em ip tera ▁of ▁South ▁America ▁Category : End em ic ▁fa una ▁of ▁Brazil ▁Category : Environment ▁of ▁Santa ▁Cat arina ▁( state ) ▁Category : D ip tera ▁used ▁as ▁p est ▁control ▁agents ▁Category : In sect s ▁used ▁for ▁control ▁of ▁invas ive ▁plants ▁Category : In sect s ▁described ▁in ▁ 1 9 4 8 ▁Category : E cc rit ot ars ini <0x0A> </s> ▁The ▁emb ry ological ▁origin ▁of ▁the ▁mouth ▁and ▁an us ▁is ▁an ▁important ▁characteristic , ▁and ▁forms ▁the ▁morph ological ▁basis ▁for ▁separ ating ▁bil ater ian ▁animals ▁into ▁two ▁natural ▁group ings : ▁the ▁proto st om es ▁and ▁de uter ost om es . ▁ ▁In ▁animals ▁at ▁least ▁as ▁complex ▁as ▁an ▁earth w orm , ▁a ▁dent ▁forms ▁in ▁one ▁side ▁of ▁the ▁early , ▁s ph ero idal ▁emb ry o . ▁This ▁dent , ▁the ▁bl ast op ore , ▁deep ens ▁to ▁become ▁the ▁arch enter on , ▁the ▁first ▁phase ▁in ▁the ▁growth ▁of ▁the ▁gut . ▁In ▁de uter ost om es , ▁the ▁original ▁dent ▁becomes ▁the ▁an us , ▁while ▁the ▁gut ▁eventually ▁t unn els ▁through ▁the ▁emb ry o ▁until ▁it ▁reaches ▁the ▁other ▁side , ▁forming ▁an ▁opening ▁that ▁becomes ▁the ▁mouth . ▁It ▁was ▁originally