10 



One male, one female, coUeeted while hoveringj in herbage. 

 Type locaUty: — Tafi Viejo, Tuciimán (14.3.27, R. C. Shannon). 

 Named for Doctor Martin Doello-Jnrado, director of the Museum 

 of Natural History, Buenos Aires. 



PipuncnJus lynchi, new speeies. 



A small (2.5 mm. ; winp; 3 mm.) shining black speeies, easily 

 disting'uished by its wing venation and the presence of an obtnse spiír 

 on the posterior troehanter. Antenna black; third joint produced 

 into a long tapering point below ; ocellar and frontal triangles long, 

 so that the eyes are contiguous only for a distance of six f aeets ; thorax 

 black, palé yellowish ; legs black, the bases of the tibiae and the tar.si 

 obscnrely yellow ; abdomen shining black ; halteres yellowish. 



One male. 



Type locaUty: — Tafi Viejo, Tiicuman (14.3.27, R. C. Shannon). 



Family Syrphidae. 



This family is one of the best known gronps of Díptera in Argen- 

 tina, as a resnlt of the excellent treatist pnblished by F. Lynch Arri- 

 balzaga (Anales de la Sociedad Científica Argentina, vols. 32, 33, 34, 

 in instalments, 1891-1893) which still remains the major work on the 

 family in this eonntry. 



It is therefore unnecessary, at present, to give a complete descrip- 

 tion of the family, or for the genera here treated. 



Genus Microdon Meigen, 



An apparently new speeies was recently found in association wdth 

 a colony of ants {Camponotus (Myrmohrachys) nms Rog. ; det. Bruch) 

 at Alta Gracia, Córdoba. 



Two females were eaptured; one of them was taken while in the 

 fict of laying eggs in the middle of the trail (on the side of a rock) 

 of the ants which were going to and from to their nest, sitnated nniler 

 a hngh rock. Perhaps the eggs are picked np by the ants and carried 

 into the nest where the larvae npon hatching find themselves in a 

 siiitable environment. 



Microdon hrucM, new speeies. 



Female : — Fairly large and robust (length 12 mm. ; wing 

 9.5 mm.) ; general coloration dark bronze; wing veins infuscated. 



Head: — Front a little more narrow than width of face, slightly 

 widening downwards, bronzy black in coloration, clothed with black 

 hairs on upper half and ,yellow hairs on loM-er half; antennae very 

 elongate, black; proportionate length of joints: 1.0: 0.25: 1.10; (total 

 length 3 mm.) arista equal to three-fourths the length of the first ' 

 joint ; the face is slightly more than one-third the headwidth, gently 

 arched in profile and uniformly clothed with yellow hairs. 



