ASHMEAD : CLASSIFICATION OF THE CHALCID FLIES 265 



4. Antennae with three ring-joints 5 



Antennse with two ring-joints. 



Head and thorax umbilicately punctate, the parapsidal furrows wanting ; prouotum as wide as 

 the mesonotum, the hind margin arcuately emarginate ; flagellum filiform, pubescent, the 

 joints subquadrate Neorileya Ashmead. 



5. Head and thorax smooth or nearly, at most very finely punctate or microscopically shagreened, the 



parapsidal furrows sometimes delicate but distinct. 



Pronotum as wide as the mesonotum, more than twice wider than long ; abdomen ovate, the 

 fourth segment very long; flagellum filiform, pubescent, the joints of the funicle nearly 



equal, a little wider than long Rileya Ashmead. 



Pronotum quadrate, nearly as long as wide and a little narrower than the mesonotum ; abdomen 

 elongate, cylindrical, as long as the head and thorax united, the segments subequal ; flagellum 

 subclavate, gradually thickened towards the tip, the last two joints of funicle transverse. 



Macrorileya Ashmead. 



Teibe V. Decatomini. 



This tribe is very closely allied to the tribe Eurytomini, but is readily separated 

 from it and the other tribes by the much thickened or stigmated marginal vein, 

 and by the antenna being alike, or very similar, in both sexes. The hind tibiae are 

 always armed with rigid bristles behind. Some of the Eurytomini, however, also 

 have similarly armed tibiae, so that this character in itself is not sufficient to dis- 

 tinguish the group. 



All the species are parasitic upon hymenopterous and dipterous gall-makers. 

 ( Cynipidss and Ceddomyiidse). * 



Only two genera fall into this tribe, distinguished as follows : 



TABLE OF GENERA. 



1. Females 2 



Males 3 



2. Wings hyaline, with a dusky submarginal blotch or band ; antennje 9-jointed, with one ring-joint, the 



club usually not jointed, if with 3 indistinct joints, 11-jointed, pedicel obconical, nearly thrice as long 



as thick at apex Decatoma Spinola (type Diplolepis adonidum Rossi). 



Wings hyaline, without a dusky submarginal blotch ; pedicel shorter, not or hardly twice as long as 

 thick at apex Eudecatoma Ashmead (type E. batatoides Ashmead). 



3. Wings hyaline, with a dusky or fuscous submarginal blotch or band Decatoma Spinola. 



Wings hyaline, without a dusky submarginal blotch ; all femora considerably swollen. 



Eudecatoma Ashmead. 



Family LXIV. PERILAMPID^. 

 1846. Eucharidse, Family (partim), Walker, List Chalc. Brit. Museum, I., p. 103. 

 1856. Perilampoidse, Family IX., Forster, Hym. Stud., XL, pp. 19, 22 and 46. 

 1875. Perilampina, Tribus, Thomson, Hym. Skand., IV., pp. 11, 22. 

 1886. Perilampinge, Subfamily, Howard, Ent. Amer., I., p. 198. 



