SYNOPSIS OF XORTH AMERICAN SYRPHID.E. ^ 



tellum brownisli red, small, oval, without spines or tubercles. Abdo- 

 men elongate oval, nearly bare, finely punctulate; second and third 

 segments yellow ; fourth elongate, black. Legs luteous yellow, the 

 femora chiefly black; hind metatarsi elongate, somewhat thickened, 

 scarcely dilated. Wings dark brown, less so behind. Cross-veins much 

 inflected, sinuous, but without stumps. 



One specimen, Georgia (National Museum, Professor Riley's collec- 

 tion), A female specimen from Texas differs in having the abdomen 

 broadly oval, and nearly uniformly brown, the anterior segments lute- 

 ous in the middle. 



Microdon falcatus, n. sp. 

 Habitat. — Mexico ! 



9 . Length, 5°^'". Head flattened, vertex projecting, front descend- 

 ing. Front and face reddish yellow, shining, nearly bare. Antennae 

 elongate, black; first joint slender, second short, third longer than the 

 first two together, thickened, curved falcate. Eyes bare. Thorax yel- 

 lowish red, nearly bare; dorsum with three coalescent, black stripes, 

 the outer ones abbreviated in front and behind, the middle one behind ; 

 scutellum very slightly emarginate behind. Abdomen red or brownish 

 red, i)aler toward the base, very broadly oval, depressed, nearly bare. 

 Legs black; hind tarsi scarcely dilated. Wings cinereous hyaline, 

 strongly pubescent; the veins stout, nearly black; last section of the 

 fourth vein inflected, posterior cross- vein sinuous. 



Four specimens, Isthmus of Tehuantepec (National Museum, Pro- 

 fessor Eiley's collection.) 



Microdon aurifex. 



Microdon aurifex Wiedemann, Auss. Zw. Ins., ii, 85 ; Macquart, Dipt. Exot., ii, 2, 



11, 2, tab. ii, fig. 2. 

 ? Microdon irocMlus Walker, Dipt. Saunders., 216. 



^« 6 ^/«t— Mexico!, Brazil (Wied.). 



$ . Length, 10"^"°. Bright metallic green with violaceous reflections j 

 tip of the abdomen yellow; legs black. Antenna; blackish brown, 

 first and third joints of nearly equal length. Face rather narrow, mod- 

 erately swollen, white pilose. Front with black pile, considerably nar- 

 rowed in the middle, where its breadth is less than half the distance 

 between antennae and ocelli. Eyes sparsely pilose. Dorsum of thorax 

 ■with moderately abundant erect black pile ; in front and on the sides, 

 with sparse, light yellow pile. Scutellum large, trapezoidal, covered 

 with light yellow pile ; spines small and remote. Abdomen less viola- 

 ceous than the thorax, nearly bare; first segment with yellow pile : sec- 

 ond with an anterior opaque black cross-band; hypopygium wholly 

 reddish yellow, not shining. Legs black, with a greenish reflection, es- 

 pecially on the hind pair ; pile black, rather long, fringed on the outer 

 side of the tibiae, particularly of the hind pair; hind tarsi considerably 

 dilated. Wings nearly uniformly cinereous; posterior cross-vein not 

 much inflected, without stump. 



