8. CHLOROMYIA 187 



8. CHLOROMYIA. 



Chloromyia Duncan, Mag. Zool. Bot., i., 146, 164 (1837). 



Moderate-sized brilliantly shining green flies, stouter than 

 Sargus but more elongate than Microchrysa, and diflfering from 

 both by the densely hairy eyes. 



Head wide, being slightly wider than the thorax and also much wider than deep ; 

 face small but inflated and conspicuously hairy ; jowls small ; back of the head 

 hardly hollowed out; vertex raised and rather conspicuously pubescent. Eyes 

 densely hairy, touching for a considerable distance in the 

 male and with enlarged facets in that sex on the upper 

 part, but widely separated and with equal facets in the 

 female. Antennae (fig. 141) rather long; third joint with 

 four distinct annulations, of which the three Ijasal ones 

 form nearly equal rings, but the fourth one is very much 

 smaller and emits from its extreme dorsal base the_ long 

 thin arista, which is therefore not quite apical and which is Fig. 141.— 



slightly plumose about its thickened base. CMoromyia jormosa 9. x 20. 



Thorax subguadrate, rather longer than broad, and very 

 slightly widening from the front to the back, rather densely pubescent, but not 

 enough to obscure the brilliant ground colour. 



Abdomen rather broad, being about twice as long as broad in the male, but 

 broader and shorter in the female. 



Legs simple, just as in Sargus. 



Wings with a Sargus-WkQ venation, but the apparent two upper branches of the 

 cubital vein much fainter, the cubital cell shorter because the cubital vein is less 

 arched, the third veinlet from the discal cell fainter and less complete, the discal 

 cell less produced at the emission of the upper veinlet, and the lower cross -vein 

 shorter. Thoracal squamae forming an almost circular disc. 



This genus is easily distinguished from any other of the Sarginw in 

 Europe by its densely pubescent eyes ; it is also distinguished from Sargus 

 hj the eyes of the male touching on the frons, by the broader shape, and 

 by the more elongate antennse (fig. 142) which have the third joint by no 

 means globular and with three distinct almost equal annulations which 

 are followed by the small terminal one; from Microchrysa it is distin- 

 guished by the larger size, densely hairy eyes, more elongate shape, and 

 differently formed third antennal joint on which the arista is more 

 apical. 



Chloromyia is limited to the two closely allied European species and 

 one from the Cape of Good Hope, as I believe the North American S. 

 viridis to be a true Sargus of which S. frontalis Lw. (which was described 

 subseqviently from Europe), is a probable synonym, while Walker's S. 

 sapphirinus from "East Indies" requires confirmation. The larva of 

 C. formosa lives in garden mould and has been bred from Brassica ra]3a, 

 while the perfect insect is common in gardens and is fond of sunning itself 

 on leaves. 



Synom/mi/.— The first attempt at dividing the genus Safins as restricted by 

 jNIeigen was made by Macquart, who in 1834 formed a genus Chrysomyia for the com- 

 bined genera Chloromyia and Microchrysa; in 1837 Duncan, in ignorance of 

 Macquart's genus, formed a precisely equivalent genus Chloromyia, but Macquart's 

 name was inadmissible because Desvoidy had in 1830 already proposed a genus 

 Chrysomyia in the Muscicke and consequently Duncan's name must stand. It is 

 fortunate that Osten Sacken rescued Duncan's name from oblivion, as his litjtle- 



