Thaumastocoris peregrinus n. sp. from Argentina is described. New morphological characters are studied and compared with other related species. This is the first record of a member of the subfamily Thaumastocorinae (Thaumastocoridae) from the New World.

Ilustraç6es de corpo inteiro e genitália do macho acham-se incluidas. PALAVRAS-CHAVE: Mir{dios neotropicais novas espécies tribo Resthenini. ABSTRACT The authors describe seven new species of Resthenini Reuter (Hemiptera, Miridae) as follows : Nanniresthenia penai, sp. n

A new genus and species, Williamsocoris ornatus (Schizopteridae: Hypselosomatinae), is described from Argentina. This is the first record of the subfamily in South America. The particular structures of the rostrum of this new taxon are unique in the family.

Comefulvius chingonus Carvalho & Carpintero, the only representative of the genus Comefulvius, previously known only from Córdoba Province, Argentina, is recorded from Ecuador. Redescription of Comefulvius is given along with color photographs of the adult and illustrations of the male genitalia.

Between November 1999 and September 2001, mirid nymphs (Hemiptera: Miridae) were collected on wild and cultivated plants in central and northern Argentina and southeastern Paraguay. In the laboratory, nymphs were reared until adult emergence. Four (Bryocorinae, Deraeocorinae, Mirinae, and Orthotylinae) of the eight mirid subfamilies were collected during the study. Twenty-two mirid species on 43 putative host plant species were collected in Argentina, and Þve species of mirids on eight plant species were collected in Paraguay. Eighty-Þve new miridÐplant associations were recorded (only 112 miridÐplant associations had been reported previously for Argentina). Most of the mirids were in the subfamily Mirinae, tribe Mirini, and most of the host plants belonged to Asteraceae. Almost all mirids were collected on plants with ßower buds present. In addition to host plant records, the phenology and pattern of plant use for the most abundant mirids are reported. Mirid richness and abundance varied according to the host plant species; the highest diversity and richness of mirids occurred in the western region of Argentina (Salta, Jujuy, and Tucumán provinces). The most frequently collected mirid, Taylorilygus apicalis (Fieber) ('87% of the 35,970 collected mirids), was usually collected on Asteraceae. This exotic species could have affected the native mirid fauna in the study area. More research on the possible interactions between T. apicalis and the native mirids of Argentina and Paraguay is needed. Our results suggest that T. apicalis exhibits regional polyphagy, i.e., uses numerous hosts throughout its geographic range. RESUMEN Entre Noviembre de 1999 y Septiembre de 2001, ninfas de mṍridos (Hemiptera: Miridae) fueron colectadas sobre plantas silvestres y cultivadas en centro y norte de Argentina y el sudeste de Paraguay. Las ninfas colectadas se criaron hasta el estado adulto en el laboratorio. De las eight subfamilias de mṍridos conocidas, se colectaron four en este estudio: (Bryocorinae, Deraeocorinae, Mirinae, y Orthotylinae). En Argentina, 22 especies de mṍridos fueron colectadas sobre 43 especies de plantas, y 5 mṍridos sobre ocho plantas en Paraguay. Un total de 85 asociaciones planta-insecto nuevas fueron registradas (112 eran conocidas previamente en Argentina). La mayorṍa de los mṍridos colectados pertenecṍan a la subfamilia Mirinae, tribu Mirini, mientras que las plantas hospedadoras pertenecieron a la familia Asteraceae. La casi totalidad de los mṍridos fueron colectados sobre plantas con ßores presente. Además de los datos sobre las plantas hospedadoras de los mṍridos, se presentan datos sobre fenologṍa y patrones de utilizació n de las plantas de los mṍridos más abundantes. En general la riqueza y la abundancia de los mṍridos varió de acuerdo a las especies de las plantas hospedadoras; la mayor diversidad y riqueza de mṍridos se observó en el oeste de Argentina (en las provincias de Salta, Jujuy, Tucumán). Taylorilygus apicalis (Fieber) fue el mṍrido más abundante (87% de los 35.970 mṍridos colectados) y ...