ASHMEAD : CLASSIFICATION OF THE CHALCID FLIES 273 



This su^bfamily seems to be a, natural group of gall-inhabiting species, allied to 

 the Pireninse, but easily separated by the structure of the antennEe. 

 Two tribes may be distinguished : 



TABLE OF TRIBES. 



Mesonotum with complete, distinct fun-ows Tribe I. Tridymini. 



Mesonotum with incomplete furrows, indicated only anteriorly Tribe II. Metastenini 



Tribe I. Tridymini. 

 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 family Cecidomyiidx. ^pocerus Mayr, however, is a genus living parasitic- 

 ally upon fig-insects in Brazil, and one or two exotic genera attack other gall- 

 inhabiting insects. 



TABLE OF GENERA. 



1. Females 2 



Males 15 



2. Antennse inserted near the mouth or just above the clypeus 3 



Antennse inserted on or near the middle of the face, far above the clypeus 8 



3. Marginal vein noi'mal 4 



Marginal vein abnormal, semicircularly thickened at the base Stigmatocrepis Ashmead g. nov. 



(type S. americana Ashm.). 



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



Clypeus at apex triangularly produced. 



Antennse 12-jointed, the flagellum clavate, the joints of the funicle quadrate or transverse ; 

 abdomen ovate or conic ovate Tridymus Ratzeburg (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. 



Front wings hyaline, sometimes with a smoky discoidal cloud, the marginal vein much longer 

 than the stigmal, the latter with an upward curve, the first marginal vein not longer 

 than the stigmal ; antennse 13-jointed with 2 ring-joints, the pedicel not long. 



Decatomothorax Ashmead g. nov. (type D. gallicola Ashm.). 



6. Head and thorax finely punctate or shagreened, 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 ; antennte 13-jointed, with 2 

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

 of the funicle united AUoderma Ashmead g. nov. (type A. maculipennis Ashm.). 



7. Abdomen conically produced, the ovipositor exserted ; antennse 12-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 ; antennse 13-jointed, the funicle 6-jointed, 



the joints short, nearly cup-shaped Oxyglypta Forster. 



