AN ANNOTATED PRELIMINARY LIST OF THE CHIRONOMIDAE (DIPTERA) OF ZURQUÍ, COSTA RICA Abstract Introduction Author Epler, John H. 461 Tiger Hammock Road, Crawfordville, Florida, 32327, U. S. A. johnepler3@comcast.net text CHIRONOMUS Journal of Chironomidae Research 2017 2017-04-21 30 30 4 18 https://www.ntnu.no/ojs/index.php/chironomus/article/view/2240 journal article 10.5324/cjcr.v0i30.2240 2387-5372 7987298 Metriocnemus - Three species, two undescribed, were collected. The named species, Metriocnemus costatus , was described from Guatemala by Sublette & Sasa (1994) . Their description stated “genitalia with a midventral notched, somewhat quadrangular plate”. One of the Metriocnemus species collected, initially designated M . sp. ZUR-2, was very similar to the description and illustrations for M. costatus ( Sublette & Sasa 1994 : fig. 88) except it apparently lacked this plate. I was able to examine 6 paratypes of M. costatus from the Sublette Collection, located at the University of Minnesota, St. Paul, MN. The specimens were all excessively squashed (typical of Sasa mounts) and the quadrangular plate was apparent. I then remounted the abdomen/genitalia of one of the Zurquí M. sp. ZUR- 2 specimens and excessively squashed it – the quadrangular plate appeared! This plate is normally oriented in a dorsal-ventral manner and is visible as a thin sclerotized line when viewed in a typical genitalia mount that has not been excessively flattened. The structure may represent the aedeagus or an ejaculator (see Tuxen 1970 : fig. 160).