Sympotthastia Pagast (Diptera: Chironomidae), an 



Update Based on Larvae from North Carolina, 



S. diastena (Sublette) comb, n., 



and Other Nearctic Species 



Jan S. Doughman 1 



U. S. Geological Survey, 



National Water Quality Laboratory, 



6481-H Peachtree Ind., Doraville, Georgia 30340 



ABSTRACT. — Chironomids from the Nearctic believed to belong to 

 Sympotthastia Pagast have been verified. They have been described 

 and keyed against the well-known Palaearctic species. Generic descrip- 

 tions of the male imago and pupa are expanded to include these spe- 

 cies. Species found in the Nearctic in the larval stage, S. fulva 

 Johannsen, a species near fulva, and S. zavreli Pagast, are contrasted 

 with a generic larval description. The nearctic S. diastena (Sublette) 

 comb, n., known only in the adult stage, is redescribed using two 

 imagos collected in Oregon. 



INTRODUCTION 



This paper offers a taxonomic and ecological summary of all 

 known species of Sympotthastia, which should be identifiable using the 

 generic descriptions and keys provided. Species are separable only by 

 minor differences, but two species groups are discernable. 



The Palaearctic S. zavreli-group consists of S. zavreli Pagast, S. 

 spinifera Serra-Tosio, and S. macrocera Serra-Tosio. Most of these spe- 

 cies are well described in all stages (Serra-Tosio 1971, Ferrarese and 

 Rossaro 1981). An unassociated larva found in North Carolina is keyed 

 and described herein as zavreli (cf. Thienemann 1952), and this is the 

 only member of the zavreli-group to be found in the Nearctic. 



The Nearctic S. fulva-group consists of S. fulva (Johannsen), S. 

 diastena (Sublette), a species near fulva, known in the larval stage, and 

 a pupa described by Saether (1969). 



Sympotthastia fulva was described at all stages by Johannsen 

 (1921, 1937) with an emended description of the adults by Sublette 

 (1967). I believe that this species is properly placed because the imagoes 

 of both sexes were described from associations with the immatures 

 reviewed for this paper. Dr. Dean Hansen identified two slides of male 

 imagoes as S. diastena. This is a new combination with which I concur; 



•Present address: U.S. Geological Survey— WRD, FB^4, 301 W. Congress, 

 Tucson, Arizona 85701 



Brimleyana No. 1 1 :39-53, October 1985 39 



