2 Orthorrhapha brachycera. 



rather short to a half times longer than the head is high ; it is straight 

 or nearly so, only in Xiphocerus curved inwards towards the end; 

 the proboscis is directed downwards or more or less forwards, truncate 

 or more pointed at the apex. Labrum is short. generally of the length 

 of the basal part of labium; hypopharynx is strong, semitubular and 

 pointed at the apex; the upper edges of the semitube are beset with 

 erect hairs over more or less of the apical part or nearly the Avhole 

 length; the hypopharynx is used to sting with. The maxillæ are also 

 rather strong with a long, pointed or truncate, sometimes semitubular 

 lacinia and with one- or two-jointed palpi. Labium has the basal 

 part occupying more or less of the length up to the half part; the 

 apical part is more or less distinctly divided^ into two joints, some- 

 times undivided; this apical part answers to the labella but is not 

 developed as such but strongly chitinised like the basal part, and below 

 it is not divided in the middle line. Generally the division between 

 the basal and the labellar part is somewhat distinct; at the apex the 

 labellar part is more or less beset with hairs, and the basal part has long 

 hairs below. Hypopharynx and maxillæ are about equal to the length 

 of the labium. Thorax is high, more or less arched above; it is rect- 

 angular or nearly oval. It bears often macrochætæ and then generally 

 præsutural, supraalar, postalar and also dorsocentral bristles, and 

 on the scutellum marginal bristles. Sometimes macrochætæ are not 

 developed. On the metapleura there is generally a vertical row of 

 bristles or strong hairs, often also continued down the hypopleura. 

 The prothorax is distinctly developed; it is narrow, and hence the 

 head is free, not lying towards the front end of the thorax. The pro- 

 thorax has a transverse row of hairs or bristles above. The meta- 

 thorax is also rather distinctly developed, the dorsum is generally small 

 but the metasternum is moderately large, and the space between it 

 and the hind coxæ is filled up by a membrane, Abdomen is long 

 and generally narrower than the thorax; sometimes it is very slender. 

 It is generally cyhndrical, sometimes more flattened or on the contrary 

 somewhat compressed. It consists of eight segments, but often one 

 or even more of the last are small or hidden. The first dorsal seg- 

 ment is always short and generally broader than the folio wing one 

 which is as a rule the longest; the first ventral segment, foUowing 

 after the metasternum, is nearly always very short. The male geni- 

 taha are large and projecting; they seem in all cases to be formed of 

 parts of the segment or segments following after the eighth. I have 

 not been able to work out in all cases the homologies in the different 

 genera, but generally the genitalia consist of the upper forceps, and 

 below this the lower forceps; between the arms of the upper forceps 



