THE IDENTITY OF CHAETOCLUSIA AFFINIS 
JOHNSON AND ITS PLACEMENT IN 
SOBAROCEPHALA CZERNY 
(DIPTERA: CLUSIIDAE)* 
By Norman E. Woodley 
Systematic Entomology Laboratory, IIBIII, ARS, USDA 
c/o U. S. National Museum of Natural History 
Washington, DC 20560 
Johnson (1913) described Chaetoclusia affinis on the basis of one 
male and one female from New Jersey. His brief and inadequate 
description has not allowed subsequent authors to recognize the 
species and omits discussion of characters later used to define clusiid 
genera. Melander and Argo (1924) simply repeated Johnson’s 
description and mentioned that they had not seen his material. 
I have recently examined the holotype male and allotype female 
of C. affinis, which are housed in the Museum of Comparative 
Zoology at Harvard University (MCZ #7873). It was readily 
apparent that Johnson had placed the species in the wrong genus, 
and that C. affinis actually belongs in the genus Sobarocephala 
Czerny, not Chaetoclusia Coquillett. Both of Johnson’s specimens 
lack the longer, bristle-like hairs on wing vein R,, which are 
characteristic of Chaetoclusia. Johnson probably placed the species 
in Chaetoclusia because of its densely pubescent antennal arista, a 
character state found in Chaetoclusia bakeri Coquillett, the type 
species of the genus. This feature, however, is not unique to 
Chaetoclusia, and in fact partially defines the “plumata” species 
group of Sobarocephala, as recognized by So6s (1963). 
When S. affinis is run through the most recent key to Nearctic 
Sobarocephala (Sabrosky and Steyskal, 1974), it runs without 
difficulty to S. testacea So6s. The holotype male of S. testacea, 
housed in the U. S. National Museum of Natural History, was 
recently examined and found to be conspecific with S. affinis. 
Johnson’s allotype is probably also conspecific, but there is 
difficulty in separating females of this species from those of S. 
muesebecki Sabrosky and Steyskal. The latter species is known with 
* Manuscript received by the editor February 15, 1984. 
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