A REMAEKABLE NEW GENUS AND SPECIES OF TWO- 

 WINGED FLIES RELATED TO THE OESTRIDAE 



By Charles H. T. Townsend 

 Itaquaquecetuha , Sao Paulo, Brazil 



Dr. J. M. Aldrich has asked me to name and describe an extremely 

 interesting fly which he sent me for examination and which I be- 

 lieve to be the most important oestromuscoid discovery of the twen- 

 tieth century from the taxonomic point of view. 



After long deliberation, I arrived some years ago at the con- 

 clusion that the oestriform tachinids or Tachino-Oestridae of 

 Villeneuve (Aulacephalini, Ormiini, Trixodini, Trixini, Palposto- 

 matini, Paratrixini, Glaurocarini, and Myiotrixini) all belong in the 

 same family with the Oestrini, despite the apparent gap between 

 the last-named tribe and all the others. There was no known form 

 that would fit in the Oestrini better than in any of the other tribes 

 and yet show some of the widely different characters of the latter, 

 such as well-developed macrochaetae, developed haustellum, and 

 ventral membrane concealed. 



The present form closes this gap between the Oestrini and the 

 other tribes of Oestridae above named. Its venation and head 

 conformation are both strikingly oestrine and preclude its reference 

 to any of the other tribes, yet the ventral membrane is concealed, 

 the proboscis is considerably developed, and the bristles are well 

 developed. 



OLIGOOESTRUS, new genus 



Genotype. — Oligooestrus oestroideus^ new species. 



Male. — Form moderately narrowed. Head (fig. 1) subelliptic in 

 front view, roundly bulging below, about one-fourth wider than 

 high, its profile subsemicircular ; frontal profile flat, well sloped, 

 twice as long as facial profile to vibrissae; facio-oral profile arcuate; 

 clypeus depressed, cuplike, a little longer than wide, no facial carina ; 

 epistoma nearly twice as long as clypeus, arcuately receding, some- 

 what over half as wide as clypeus, a little widened above and more 

 below; facialia bare, half as wide as clypeus, obliquely flattened; 

 vibrissae decussate, longer than the bristles below them; vibrissal 



No. 2942.— Proceedings U. S. National Museum, Vol. 82, Art. I 



129571—32 1 



