Prosoeca difficile (Bequaert) Barraclough, 2005

Barraclough, David A., 2005, A review of the type material of the Southern African genus Stenobasipteron Lichtwardt, 1910 (Diptera: Nemestrinidae), with transfer of two species to Prosoeca Schiner, 1867, Zootaxa 1094 (1), pp. 41-51 : 49

Prosoeca difficile (Bequaert) , comb. n.

Stenobasiopteron difficile Bequaert, 1925: 11 .

Holotype ♀: Zimbabwe: Cloudlands , 6000’ [high altitude grassland] / Vumba Mts / ♀ S. Rhodesia / 6–17 April 1929 / Rhodesia Museum; Stenobasipteron / difficile / type ♀ J. Beq. / J. Bequaert det.; TYPE [rectangular red card]. The holotype (in NMBZ) is in good condition. There is no other type material.

Discussion: In his original description, Bequaert remarked on the very close similarity between Stenobasipteron difficile and S. gracile , and listed seven characters which supposedly separated the species. This comparison is however incorrect, as Bequaert appears not to have examined the type material of S. gracile , and the material of S. gracile used for the comparison was misidentified as S. difficile (see above under S. arnoldi ).

I have examined the male syntype of S. gracile (a female syntype is the only other specimen in the type series), and there are several major characters separating it from S. difficile . The most important character is the development of vestiture on abdominal terga 3 and 4. S. difficile has obvious erect vestiture on these terga, unlike S. gracile which has inconspicuous, recumbent vestiture, characteristic of other Stenobasipteron species. As my diagnosis of Stenobasipteron includes only species with recumbent vestiture, I herewith transfer S. difficile to Prosoeca . It should be noted though that Prosoeca difficile , comb. n. does have a reduced alula, which was previously considered to characterise only Stenobasipteron species. The species are otherwise easily distinguished by colour characters. S. gracile is a pallid species with reddish­brown legs and very pale brown infuscated wings, whilst Prosoeca difficile is a dark species with yellow legs and relatively dark brown infuscated wings.