ashmead: classification of the chalcii) flies 273 



This subfamily seems to l)e a natural group of gall-iiilialiitiiig species, allied to 

 the Pireniiuv, but easil}'^ separated by the structure of the anteniue. 

 Two tribes may be distinguished : 



table of tribes. 



Mesonotum with complete, distinct fiiiiows Tribe I. Tridymini. 



Mesouotuui with incomplete furrows, iiulitati'd only anteriorly Tribe IL Metasteuini 



Tkikk 1. Tndiinunl. 

 The complete mesonotal furrows distinguish this tribe. Most of the species fall- 

 ing in this tribe are parasitic upon gall-making or gall-inhabiting Diptera, belonging 

 to the famil}' Cecidorui/ildn: J\jtnarn.s Mayr, however, is a genus living parasitic- 

 ally upon fig-insects in Urazil, ami one or two exotic genera attack other gall- 

 inhabiting insects. 



TABLE OF (iENERA. 



1. Females 2 



Males 15 



2. Antenna; inserte<l mar the moutli or just abuvc the clypeus 3 



Antennae inserted ou or mar Uic luiddlc ol' the face, far above tlie elypeus 8 



3. Marginal vein normal 4 



Marginal vein abnormal, semieireularly tliitkciied at the base Stigmatocrepis Ashmead g. nov. 



(type .S'. americana Aslmi.). 



4. Clypeus at apex truncate or with a slight median simis, never produced 5 



Clypeus at apex triangularly produced. 



Antennae 12-jointed, the flagellum clavate, the joints of the funicle quadrate or transverec ; 

 abdomen ovate or conic ovate Tridymus Katzeburg (type T. aphidum Ratz.). 



5. Head and thorax not umbilicately punctate, at the most finely punctate, shagreened or rugulose, some- 



times smooth 6 



Head and thorax umbilicately punctate. 



F'ront wings hyaline, sometimes with a smoky discoidal cloud, the iii;ugiiial \ciii much longer 

 than the stigmal, the latter with an upward cur\ e, the lust marginal \ein not longer 

 than the stigmal ; antenna' 13-jointed witli 2 ring-joints, tlie pedicel not long. 



Decatomothorax Ashmead g. nov. (type D. gallivota A.shm.). 



6. Head and thorax finely punctate or shagrcenod, rarely smooth 7 



Head and thorax finely rugulose ; marginal vein not longer than the stigmal vein, the latter .straight, 



but oblique, not curved, postmarginal vein longer than the stigmal ; antenn;e 13-jointed, with 2 

 ring-joints, the pedicel large, as long as or a little longer than the ring-joints and the tirst joint 

 of the funicle united Allodenna A.shmead g. nov. (type A. maculipennis Ashm.). 



7. Abdomen conically produced, the ovipositor exscrted ; antenna^ iL'-jointed, the funicle joints trans- 



verse ; marginal vein more than twice the length of the stigmal vein Gastrancistrus Westwood. 



(type G. vagans Westw.). 



Abdomen short oval, above; depressed, beneath boat-shaped ; antenna- l;!-jointcd, the funicle 6-jointed, 



the joints short, nearly cup-shaped Oxygl3T)ta Forster. 



