Four new species of Alloxysta Förster are described (A. andrewsi Ferrer-Suay & Pujade-Villar n. sp., A. costaricensis Ferrer-Suay & Pujade-Villar n. sp., A. hansoni Pujade-Villar n. sp. and A. luismii Ferrer-Suay n. sp.) from Costa Rica being the first records of this genus in this area. Their morphological features and diagnostic characters are illustrated. We provide a diagnosis of Apocharips hansoni Menke with a detailed description of the radial cell, which expands the characteristics of the genus Apocharips.

The knowledge status of the gall-former cynipids in the Mexican oaks is commented herein. For each of the 157 cited species from 33 oak species, the most important biological and ecological information is included. Andricus championi (Cameron), a species described only from the gall, is considered as 'incertae sedis'. Andricus tumeralis Pujade-Villar nom. nov. is proposed to denominate the species Andricus ashmeadi Dalla Torre & Kieffer for being a homonymy of Andricus ashmeadi Basset. Atrusca dugesi (Mayr) n. comb. (formery in Cynips) and Antron sagata (Kinsey) n. comb. (formery in Sphaeroteras) are proposed. The reasons of these changes are commented as well as the need for further studies on Mexican cynipids.

Se comenta cual es el estado del conocimiento de los cinípidos que producen agallas en los encinos mexicanos. Para cada una de las 157 especies citadas en 33 especies de encinos, se mencionan los aspectos biológicos y ecológicos más importantes. Se considera a Andricus championi (Cameron), especie descrita solamente a partir de la agalla, como 'incertae sedis'. Se propone Andricus tumeralis Pujade-Villar nom. nov. para denominar a la especie Andricus ashmeadi Dalla Torre & Kieffer por ser homonimia de Andricus ashmeadi Basset. Se propone Atrusca dugesi (Mayr) n. comb., (antes incluida en el género Cynips) y Antron sagata (Kinsey) n. comb., (antes incluida en el género Sphaeroteras). Se exponen las razones de estos cambios taxonómicos y se señala lo mucho que queda por hacer en el estudio de los Cynipidae mexicanos.

Neralsia es un género de himenópteros de distribución americana, presente tanto en la región Neártica como en la Neotropical. En este trabajo se estudian, usando microscopia de luz y electrónica, las especies sudamericanas en su conjunto, 26 anteriormente citadas y ocho especies nuevas, que se describen aquí formalmente. Se presenta, además, una clave para su identificación; y se ilustran los caracteres que permiten definir las especies consideradas en este estudio.

Neralsia is a genus of Figitid hymenopterans present in both the Neartic and the Neotropical regions. In this work, material from several museums (including all types of the South American species of Neralsia) was analyzed with light and electron microscopy. The South American species are studied as a whole, reviewing 26 previously cited species and describing eight new species. A key for their identification is included and the characters to differentiate species here considered are illustrated. Rev. Biol. Trop. 56 (2): 795-828. Epub 2008 June 30.