ORTALID^E — PYRGOTA. 73 



Abdomen : in the male with four segments, the first of which strikingly 

 prolonged, the following ones considerably shorter; in the female 

 with five segments, the first of which very remarkably prolonged, 

 the following ones quite as remarkably shortened ; ovipositor large, 

 not flattened, almost capsule-shaped. 



Spurs of the middle tibice only bristle like ; very weak in the species 

 with less coarse hairs. 



Wings large; posterior angle of the anal cell acute; small ciossvein 

 beyond the middle of the long discal cell; third longitudinal vein 

 curved backwards towards its end ; the last section of the fourth 

 longitudinal vein arcuated, but little diverging from the third. 



Macquart's genus Oxycephala is identical with Pyrgota. 

 Harris, in his Catalogue of the Insects of Massachusetts, calls 

 this genus Sphecomyia. 



Real Pyrgotse are known to occur with certainty in North 

 America only. As in Europe and Africa genera occur, which 

 are closely allied to Pyrgota, it is not impossible that Walker's 

 P. latipennis (List of Dipt. p. 1087) from Sierra Leone is a real 

 Pyrgota; however, his description is altogether silent concerning 

 those characters which are indispensable for the recognition of 

 the genus. Whether P. pictipennis Walker (List, etc. 1162) 

 belongs to this genus is very doubtful; the author himself 

 introduces it with a doubt, but remains silent as to the motives 

 of this location as well as the cause of the doubt. 



The North American Pyrgotse at present known may be 

 divided in two groups: in the first, the arista is only two-jointed, 

 and, at the same time, the usual bristles on the vertex, as well 

 as those bristles which in other genera protect the ocelli, are 

 present; in the other group, the arista is distinctly three-jointed, 

 and there are no conspicuous bristles either on the vertex, or 

 round the spot where, in other genera, the ocelli are placed. 

 Pyrgota millepunctata belongs to the first, all the other species 

 to the last group. Were the number of the species larger, these 

 characters would justify a subdivision in two genera; at present, 

 with the small number of species, all easy to identify, this sub- 

 division would be useless. 



1* P. millepunctata Lw. 9 • — Fusco picea, seta antennali biarti- 

 culata; alae iufuscatae, guttulis numerosis subpellucidis aspersae. 



Pitch-brown; arista two-jointed ; wings infuscated, dotted with numerous 

 pellucid spots. Long. corp. 0.38 — 0.43, cum terebra 0.51 — 0.55, long, 

 al. 0.49—0.55. 



