2 



DIPTERA. 



the fourth vein ; a stump on the penultimate section of the third vein ; last section of fourth vein not 

 angulated or broken. 

 Length 10 millim. 



Hab. Mexico, La Venta in Guerrero 300 feet (H. H. Smith). 

 One specimen. 



The present species is in all respects a Microdon with a pedicellate abdomen, though 

 a true Mixoyaster. 



MICRODON. 



Microdon, Meigen, in Illiger's Magazin,, ii. p. 275 (1803). 

 Aphritis, Latreille, Hist. Nat. Crust. et Ins. xiv. p. 358 (1805). 

 Ceratophya, Wiedemann, Aussereur. zweifl. Ins. ii. p. 79 (1830). 

 Dimeraspis, Newman, Ent. Mag. v. p. 372 (1838) . 

 Mesophila, Walker, List Diptera, iv. p. 1157 (1849). 

 Ubristes, Walker, Ins. Saunders., Diptera, p. 217 (1856). 



— — — — Synepstfa of the Central-American species. 



1. Scutellum with distinct points o: spines 2. 



Scutellum rounded or emargicate, without points or spines ; 



small species .... 5, 



2. Large, resplendent green, viole*-, and coppery species ; spines of 



scutellum remote ; legs without yellow ; wings without clouds. aurifex, Wiedem. 



Not such species ; spines of scutellum approximate 3. 



3. Deep opaque black, elongate species ; wings black, with the 



extremity yellow niger, sp. n. 



Smaller, more or less metallic species 4. 



4. Slender species ; wings f asciate ; antennse short baliopterus, Loew. 



Moderately elongate species ; antennse not uimsually short ; 



wings not fasciate ? gracilis, Bigot. 



5. Legs black ; abdomen broad and flattened 6. 



Legs yellow ; hind tibiae dilated and ciliated ; abdomen yellowish- 



red ; wings hyaline Sp . ( uo . r Q y 



6. Third joint of antennse large, elongate, falcate falcatus, Willist. 



Third joint of antennai not markedly enlarged at the base . . Sp. (no. 6) . 



1. Microdon aurifex. (Tab. L figg. 2, <? ; 2 «, head.) 



Microdon aurifex, Wiedem. Aussereur. zweifl. Ins. ii. p. 85 1 ; Willist. Synopsis N.-Am. Syrphidai 

 p. 9 2 *. 



Aphritis aurifex, Macq. Dipt. Exot. ii. 2, p. 11, t. 2. f. 2 3 . 

 Microdon trochilus, Walker, Ins. Saunders., Dipt. p. 216 \ 

 ? Microdon, sp., Willist. Trans. Am. Ent. Soc. xv. p. 258 \ 



Hab. Mexico 4 , Omilteme 8000 feet, Xucumanatlan 7000 feet, Cuernavaca (H. H. 

 Smith), Isthmus of Tehuantepec 2 .— Bkazil 1 5 , Para 3 . 



* BoU. U.S. Nat. Mus. no. 31 (1886). 



