A Monograph of Egyptian Diptera. \ \ 



CYCLORRHAPHA 



ASCHIZ A 



SYRPHOIDEA 



Syrphidae 



GENERAL CHARACTERS OF THE FAMILY. 



Small to rather large flies which do not possess a frontal suture 

 bladder and witEout any distinct chaetotaxy. Head as broad as the 

 thorax or a little broader, sometimes elongate or produced in the 

 lower part. Frons more or less produced. Face moderately broad, 

 usually more or less pubescent and clothed with dust, but never 

 bristly, and sometimes quite bare, never with longitudinal furrows 

 or lateral ridges; usually it retreats below the antennae, and then 

 is produced into a central knob, after which it is excavated and 

 again produced to the upper mouth-edge. Occiput usually shallow 

 and bearing dust and pubescence which is continued to the vertex; 

 frequently the occiput is widened about the middle through an 

 inward bend of the eye. Vertex more or less triangular and never 

 bearing any bristles. Ocelli always present. Frons more or less 

 produced, sometimes conspicuously, and never bearing any bristles. 

 Eyes large, bare or pilose, usually touching, or at least approximat- 

 ed in the male, and well separated in the female. Antennae usually 

 more or less drooping, rarely porrected, and approximated at their 

 base, each consisting of three joints, with a dorsal arista on the 

 third joint; the three joints vary in length, but the third is usually 

 the longest; the dorsal arista is usually one-jointed and bare in 

 Egyptian species, although it may be remarkably plumose in other 

 Palaearctic groups and is distinctly three-jointed in the genus 

 Eumerus; occasionally this arista may become a terminal style in 

 which case the antennae are conspicuously porrected and elongated 

 (Cerioides). 



Thorax comparatively large and robust, of normal shape, 

 usually dark coloured with three paler, more or less conspicuous 



