FAMILY TACHIXID.E THE TACHIXIDS 469 



Patillalia, new genus 



Female. — Front of moderate width; two pairs of orl)itals; ocellars 

 long; outer verticals strong; cheeks narrow; face receding, the oral 

 margin not produced; proboscis short; palpi clavate; antenna reaching 

 almost to the vibrissae; arista very short pubescent. Dorsocentrals 

 and acrosticals 3-3; posthumeral and i)osterior sublateral present; two 

 sternopleurals; prosternum haired. Apical cell ending a little before 

 the wing-tip; third vein with two strong basal bristles. Abdomen oval; 

 all segments Avith marginals, the fourth with discals. Black; head white 

 pollinose; the front yellowish above; thorax with white pollen on the 

 sides, yellowish above, distinctly vittate; abdomen with very broad 

 cinereous bands on the bases of the segments. Length, 7 mm. Geno- 

 type:— P. fasciata, n. sp. (Panama). 



Agrarialia, new genus 



Male. — Front wide, only a little narrower than the face; two pairs 

 of strong orbitals; ocellars long; outer verticals strong; cheeks very 

 narrow; face retreating, the oral margin scarcely produced; ridges 

 bare; proboscis short; palpi clavate, hairy; antennse reaching practically 

 to the oral margin, the second segment short, arista very short pube- 

 scent. Acrosticals 3-3, dorsocentrals 3-4; posthumeral and posterior 

 sublateral present; sternopleurals 2-1; prosternum haired. Apical cell 

 ending well before the wing-tip; third vein bristled almost to the an- 

 terior crossvein. Abdomen elongate oval, somewhat tapering; each 

 segment with marginals, but no discals; third segment with large sexual 

 patch below. Black, cinereous pollinose, the head largely silvery; 

 mesonotum with yellowish tinge, strongly vittate; apical third of abdo- 

 minal segments shining black. Length, 7.5 mm. Genotype : — A. sexualis, 

 n. sp. (Panama). 



Aridalia, new genus 



Female. — Front about as wide as the face; two pairs of orbitals; 

 ocellars rather short and weak; outer verticals well developed; cheeks 

 very narrow; face receding, the ridges bare, the oral margin not pro- 

 duced; proboscis short; palpi weakly clavate; antennas reaching to the 

 oral margin; arista short pubescent. Acrosticals 3-3; dorsocentrals 3-4; 

 posthumeral and posterior sublateral present; sternopleurals 2-1. 

 Apical cell ending well before the wing-tip: third vein bristled to the 

 anterior crossvein. Abdomen elongate oval, tapering apically; each 



