82 DIPTEBA. 



Synopsis of tlie Central-American species. B-j • * *4 U) ** 



1. Face black & ' 



Face yellow 3 - 



2. Thorax and abdomen shining black, not pollinose carbonaria, Willist. (<J). 



Thorax and abdomen opaque, more or less yellowish pollinose . nigrifacies, Bigot. 



3. Deep black, shining species ; cheeks brown carbonaria, Willist. ( ? ). 



Red or black, opaque, more or less pollinose species .... 4. 



4. Cheeks wholly black sororcula, sp. n. 



Cheeks brown, with a yellow spot & 



5. Prevailing colour red; dorsum of thorax with confluent black 



stripes ochreiceps, Bigot. 



Prevailing colour black ; thorax black xanthops, sp. n. 



l. Physocephala carbonaria, s $ . (Tab. II. %g. 13, 2 ; is a, profile.) 



? Conops carbonarius, Bigot, Ann. Soc. Ent. Fr. 1887, p. 4>2 l . 



Male. Head wholly black, except the facial depression, which is somewhat yellowish ; the narrow facial orbite 

 with a silvery or somewhat golden sheen. Antenna> brownish-black, the first and third joints somewhat 

 reddish ; third joint more than half the length of the second ; style with a short bristly extremity, its 

 second joint prominent Thorax pitchy-black, moderately shining ; humeri lightly pollinose above ; no 

 distinct pleural pollinose stripe. Abdomen black, shining, slenderly pedicellate. Legs : coxa3 with a 

 silvery or golden sheen « trochanters yellow ; femora dark brown, sometimes more or less reddish, 

 especially the hind pair j tibia3 hghter brown, sometimes yellowish, with the base of the hind pair yellow ; 

 tarsi yellowish-i-ed, the hind pair more brownish-red ; middle tibiae on the outer side with a silvery sheen. 

 Wings dark brown in front, nearly hyaline behind ; the brown extends to the fourth vein, and, over the 

 greater portion of the discal cell, to the fifth vein ; costal cell and a spot in front of the last section of 

 the fourth vein subhyaline. 



Female. Face light yellow ; cheeks brown ; coxoe and base of the femora reddish-yellow ; vontral process of 



the fifth segment small. 

 Length 13-19 millim. 



Hdb. Mexico l , Atoyac in Vera Cruz (H. H. Smith). 



Six specimens. It seems very probable that these belong to the species described by 

 Bigot under the name of Conops carbonarius, especially so from the remarkable sexual 

 peculiarity of the colouring of the face. Bigot, however, describes the hind femora as 

 only slightly thickened at the base ; I believe that he is in error in this statement, but, 

 until this is shown, the species may be known as P. carbonaria, Willist. The second 

 abdominal segment often has a yellowish hind border. 



2. Physocephala : 



Conops nigrifacies, Bigot, Ann. Soc. Ent. Fr. 1887, p. 40 \ 



Male. Head black, the face somewhat reddish in the depression ; the front, except the vertical callosity, thc 

 cheeks, and the face covered with a yellowish dust, variable in different reflections. Antennae black, the 

 first joint and the under part of the third somewhat reddish ; third joint of the style veiy briefly acnte. 

 Thorax black, lightly yellowish- and whitish-dusted throughout ; a more pronounced spot of golden dust 

 at the inner side of each humerus ; no distinct pleural pollinose stripe. Abdomen opaque black, the 



