40 Jan S. Doughman 



see its new description below. The holotype was poorly mounted and 

 much smaller and less setiferous than these finds of Hansen, but the 

 phallapodeme unmistakably belongs to Sympotthastia. Following the 

 criteria of Serra-Tosio (1971), an attempt was made to diagram the male 

 imagoes of Sympotthastia in their phylogenetic order (Fig. 14). 



Terminology used in my keys and descriptions follows Saether 

 (1980), but Saether did not illustrate a Diamesini. Several terms used 

 for parts of the male hypopygium were seemingly interchangeable, 

 namely superior volsella and aedeagus. I decided to use his term, supe- 

 rior volsella (SVo), to describe the anteromedial portion of the phallapo- 

 deme that is apodemal in nature, that is, this structure is heavily sclerot- 

 ized and articulates with the sternapodeme. This is illustrated for the 

 Protanypini (Saether 1980: Fig. 13), but I think this structure should be 

 consistently present in some form or another in all Diamesinae. The 

 putative aedeagus is only a flaring of the lower phallapodeme in the 

 Orthocladiinae (Saether 1980:Fig. 16). Saether, however, changed his 

 terminology to aedeagus sensu Hansen and Cook (1976) for most of the 

 Diamesini. Aedeagus, or a penislike, intromittent structure, is present as 

 a secondary, microsetigerous lobe of the phallapodeme in most of the 

 species of the sister genera Potthastia and Sympotthastia. It seems 

 proper to refer to this lobe of the phallapodeme as the median volsella 

 (MVo). The Diamesini have an anteromedial, hirsute lobe, which may 

 not be very well expressed, on the gonocoxite resembling that of 

 Saether (1980: Fig. 16). This report uses Saether's term, inferior volsella 

 (IVo) for this lobe such as it exists in Sympotthastia (see Fig. 12). 



The following ratios are expressed in key as percentages: 



Leg ratio = first tarsomere/ tibia; 



Palp to face = lengths of palpal segments 2-5/ facial width at eyes; 



Venarum ratio = length of cubital vein (from the arculus to its fork)/ 

 length of medial vein. 



Sympotthastia Pagast 



Sympotthastia Pagast, 1947:457, type species, S. zavreli Pagast, orig. 

 design.; Serra-Tosio, 1968:129-130 and 1971:267-268 (descriptions of 

 adults and pupae). 



Diamesa heterodentata Botn. et C.-Cure(?), Pankratova, 1970 (incom- 

 plete larval description but spoonlike premandible possessing lateral 

 teeth). 



Nee Symp. sp. Simpson and Bode, 1980:30 (= P. gaedii Mg.). 



Male. — Color uniform and dark. Wing 3-4 mm; body 3-6 mm. Eye 

 naked between lenses (X400) and reniform. Antenna with 13 plumose 

 flagellomeres; AR usually 2-3; A relatively long and slightly swollen 

 apically below the subterminal spine. Postorbital setae biserial at mid- 



