44 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 69 



worth noting are : The very elongate front of the male and very 

 narrow front of the female about six times as long as broad across 

 ocelli; the spur on the hind coxa in both sexes (only one other case, 

 /Stilbosoma, is known to the writer where a spur actually occurs on 

 the coxa in the Syrphidae ; usually the trochantal spur, which is fre- 

 quent in Syrphidae, is called the coxal spur) ; the trochanter bears 

 an obtuse spur; the hind femur has a long tooth and a shorter one 

 subaj)ically and the hind tibia has a subapical spur. The abdomen 

 of the male is peculiar in that it is constricted at the third segment, 

 whereas the second is large, only narrowed behind. This as far as 

 known is found in only one other genus of Syrphidae, the genus 

 Bhopalosyrphus of the Microdontinae. The general rule in Syr- 

 phidae when the abdomen is constricted is to have the main constric- 

 tion at the second segment and the third broadened. 

 Type. — Location unknown. 



Genus PLANES Rondani 



A discussion of this genus with a key to all the known species is 

 given in the section dealing with the North American fauna. Two 

 South American species are here described. 



PLANES BOLIVIENSIS, new species 



Male. — Somewhat smaller than vagans.^ and differs otherwise in 

 having the ocellar triangle much broader in proportion to its length ; 

 the antennal prominence less developed; the face nearly straight in 

 profile and less retreating; the mesonotal stripes more apparent; 

 fore and mid tibiae brownish ; and the abdomen more aeneous. 



Female. — The female has the front decidedly broader than is the 

 case in vagans and the abdominal spots much less developed, being 

 quite absent on the third tergite (this may be a variation of typical 

 specimens). Length, 9 mm.; wing, 7.5 mm. 



Type.— C2^t. No. 28673, U.S.N.M. 



Type locality. — Huachi Beni, Bolivia, Septetaber (W. M. Mann, 

 while on the Mulford Biological Expedition, 1921-22). 



Male type, female allotype, male paratype. 



PLANES MINOR, new species 



Female. — Small, slender species. Front narrowed above, at vertex 

 but little broader than width of third antennal joint, more than twice 

 as wide below, greenish black, with a rather broad, faintly pollinose 

 stripe at tniddle; antennae yellowish brown; third joint longer than 

 first two together and a little more than twice as long as broad ; arista 

 slightly longer than length of antenna ; face shining black, yellowish 

 brown at oral margin, concave in profile, the keel inconspicuous; 



