PARASITIC WASPS OF BRACONID SUBFAMILY EUPHORINAE 23 
fixation, and accordingly held Microctonus and Syntretus to be 
isogenotypic. They are, however, neither isogenotypic nor synony- 
mous. Syntretus must replace Microctonus of authors, while Microc- 
tonus Wesmael is to be used for Perilitus authors, not Nees, as has 
been shown above in the discussion of that genus. 
The following brief description will distinguish the genus Syntretus: 
Head transverse but not strongly so, only slightly broader than thorax; an- 
tennae slender; scape very short, not, or but little, longer than pedicel; pedicel 
longer than thick; occiput margined; notauli usually not or faintly impressed; 
tarsal claws cleft at apices; stigma large; radial cell on wing margin longer than 
stigma and usually nearly attaining wing apex; first cubital and first discoidal 
cells confluent; second intercubitus absent; second abscissa of radius nearly 
straight; medius obsolete or very weak, at least toward base; submediella lacking; 
nervellus represented by only a short spur; first abdominal segment strongly 
petiolate, its spiracles beyond the middle; the fused second and third tergites 
broad, carinate laterally, at least toward base; ovipositor prominently exserted. 
Only one North American species belonging to this genus has been 
described. ‘Two additional species are described in this publication. 
The host associations are unknown. 
Key to Nearctic Species of Syntretus 
1. Propodeum evenly convex, completely smooth and polished, exareolate; 
stigma three times as long as broad; antennae much longer than 
headuand: thorax combined. 2 25 (1) venustus, new species. 
Propodeum with a large, more or less impressed, median area defined 
by carinae and extending nearly the entire length of propodeum; 
stigma not more than twice as long as broad; antennae not, or 
hardly, longer than head and thorax combined__-_-------__-+_-__- 2 
2. Metacarpus not distinct; radius weak; propodeum deeply excavated down 
middle; malar space at least half as long as eye 
(2) vigilax (Provancher). 
Metacarpus and radius well developed; propodeum only weakly impressed 
medially behind; malar space much shorter 
(3) brevicornis, new species. 
(1) SYNTRETUS VENUSTUS, new species 
At once distinguished from the other North American species of 
Syntretus treated in this publication by its smooth and polished, 
exareolated propodeum. 
Female.—Length 3 mm. Head transverse, although with temples convex and 
about as broad as the eyes; face slightly convex, with scattered indistinct punc- 
tures, hardly broader at level of lower eye margins than at level of insertion of 
antennae; malar space fully as long as basal width of mandible; frons, vertex, 
and temples smooth and shining; postocellar line and ocellocular line subequal, 
nearly or quite twice the diameter of an ocellus; occipital carina complete, low; 
antennae considerably longer than head and thorax combined, tapering to apex, 
28-segmented; scape not more than one and one-half times as long as thick; 
pedicel a little longer than thick and three-fourths as long as scape; first flagellar 
segment longer than scape; the following rather abruptly shorter, those after the 
second subequal, all longer than thick. 
Thorax at tegulae not distinctly narrower than head; mesoscutum polished; 
notauli entirely lacking; impression at base of scutellum large, with a low median 
carina; propodeum evenly convex, smooth and polished, with a short longitudinal 
ridge at apex on each side of abdominal foramen; side of pronotum, mesopleurum, 
and metapleurum smooth and shining; legs slender; stigma long and narrow, 
about three times as long as its greatest breadth; metacarpus distinctly attaining 
apex of radial cell; radial cell extending nearly to apex of wing, longer than the 
elongate stigma; first abscissa of radius more than half as long as greatest width 
of stigma. 
Abdomen much narrower than thorax, subcompressed, entirely polished : 
first tergite broadening slightly beyond spiracles, which are somewhat behind 
