Microlarinus lypriformis (Wollaston), the puncturevine stem weevil, was discovered at Miami, Florida, on 28 December 1971, infesting the stems of Tribulus cistoides L. Gonatocerus brunneus Girault and Polynema sp. (Mymaridae) were reared from the eggs of Microlarinus lypriformis while Euderus sp. (Eulophidae), and Neocatolaccus tylodermae (Ashmead) (Pteromalidae) were reared from the immatures of the puncturevine stem weevil. Neocatolaccus tylodermae was reared several times from the puncturevine stem weevil, indicating that it is a major parasite of the weevil in south Florida. The rearing of the mymarid, Gonatocerus brunneus, from the eggs of M. lypriformis established the first confirmed host record for the species as well as a new distributional record for the species. The discovery of the puncturevine stem weevil in Florida was a new distributional record for the species; previously, the weevil was not known east of the Mississippi River.