TWO NEW SPECIES OF PLATYGASTRIDAE (HYMENOPTERA: PROCTOTRUPOIDEA)

Abstract Synopeas osgoodi n. sp., associated with balsam gall midge, Mariaville, Me., U.S.A., and Platygaster kimballi n. sp., associated with thistle, Houlton and Belfast, Me., U.S.A., are described herein.


Introduction
Synopeas osgoodi, described herein, was collected occasionally during balsam gall midge studies, but details of the life history are unknown.
Mr. Kimball collected many specimens of P. kimballi from yellow pan traps in Houlton, Me. The species can be tentatively associated with midge larvae inhabiting thistle, based on observations made later in Belfast, Me.

Synopeas osgoodi MacGown n. sp.
DIFFERENTIAL DIAGNOSIS. Synopeas osgoodi differs from S. pennsylvanicum (Fouts 1924) by its generally lighter color, more strongly shagreened upper face and by its parallel notauli, briefly indicated posteriorly but absent in S. pennsylvanicum. S. maculipes (Ashm.) may be mistaken for S. osgoodi but has the thorax much more strongly compressed.
S. osgoodi was collected from balsam fir, and is apparently associated with the balsam gall midge, while S. pennsylvanicum was collected from milkweed.
Scape narrowed basally and apically; pedicel clavate, as long as IV; 111 tiny, bell-like; V much narrower than IV, cylindrical; VI widened and obliquely truncate apically; VII, VIII and IX subequal, loosely joined; X as long as pedicel, narrowly rounded at apex. Thorax twice longer than wide, one-third longer than high, one-third higher than wide, convex above; pronotum sparsely punctate dorsally. Mesonotum moderately punctate with sparse, regularly placed setae; notauli absent anteriorly, briefly indicated posteriorly, parallel or barely divergent; posterior mesonotal margin concavely sinuate; pronotum smooth laterally, polished, translucent in pinned specimens, the upper margin with scattered setae; mesopleura bare, translucent, sparsely setaceous near ventral margin, with a short transverse impression just beneath tegulae; metapleura with the upper margins strongly reflexed, below this an impressed line extending from that on mesopleuron; posterior margins of metapleura bordered by white setae, the dorsal margins with a few long white setae; metacoxae setose anteriorly.
Color: reddish brown, the sutures outlined darker; femora and tibiae reddish brown except basal part of tibiae lighter; tarsi yellowish, antennae light brown.
Female. Similar to male except: tergite VI elongate, triangular, equal to IV and V combined; antenna1 pedicel large, clavate; I11 minute; IV cylindrical, slightly widened apically; V and VI subequal, as wide as IV; VII, VIII, IX and X widened, bell-shaped, forming a loosely jointed, gradually incrassate club.

REMARKS.
Due to the close similarity between S. osgoodi and S. pennsylvanicum, the accompanying illustrations should be sufficient to diagnose either species. Fouts (1924) diagrammed the female antenna of S. pennsylvanicum.
Very little variation was observed among the type specimens. It is a pleasure to name the species after Dr. E. A. Osgood, Jr., University of Maine Department of Entomology.
DIFFERENTIAL DIAGNOSIS. P. kimballi differs very little from P. virginiensis (Ashm.). The holotype is slightly longer than P. virginiensis, with the anterior mesonotal corners lightly, diagonally aciculate, and the basal foveae of tergite I1 generally well defined, with fewer striae. Antennae are nearly identical except that segment 111 is 1.5 times longer than wide instead of twice longer than wide as in P. virginiensis. The abdomen is more elongate and pointed apically.
Female. Length 1.5 mm. Head in top view 1.85 times as broad as long, not especially full behind the eyes; 1.2 times wider than high in front view; occiput with 6-8 concentric striae surrounding the foramen, sparsely setaceous on the lower portion; vertex lightly shagreened around and between lateral ocelli, more strongly so between lateral ocelli and anterior ocellus, the latter set in a round, lightly shagreened depression; frons with a depressed line extending from anterior ocellus downward, becoming raised before the antennal bases. Diagonal aciculae extend downward from frontal line, these turning upward distally; minute punctures mingle with facial aciculae, giving face a mat appearance.
All antennal segments longer than wide; scape, 6 times longer than wide; pedicel, 2.6 times as long as wide, as wide apically as VI; 111, 1.5 times as long as wide, 0.6 as long as IV; IV through IX about equally long, IV twice as long as wide; V as long and wide as IV, narrowed at both ends; VI equal to V but not narrowed; VII and VIII each 1.5 times as long as wide; IX, 1.6 times as long as wide; X lanceolate, 2.7 times as long as wide, slightly narrower than IX.
Thorax, 1.1 times as long as high, 1.2 higher than wide across tegulae, 1.4 longer than wide. Pronotum aciculate laterally, sparsely setaceous around dorsal and posterior margins, bare and polished with a few minute punctures dorsally. Mesonotum pubescent, aciculate on the anterior corners, finely punctate at apex of median lobe and on adjacent areas of the lateral lobes; notauli absent on anterior fourth; apex of median lobe broadly, concavely rounded, extending over scutellar foveae and touching the scutellum. Scutellum high, pubescent anteriorly, sharply sloping posteriorly. Mesopleura closely, finely punctate; metapleura and propodeum densely pubescent.
Abdomen 1.4 times as long as thorax; tergite I twice as long as wide, bare, with deep longitudinal striae; tergite 11, 1.1 times as long as wide, bare; basal foveae shallow, striate only on the inner margins, the striae extending nearly to the middle of the tergite; median area broad, with vague longitudinal aciculae. Tergites I11 to VI subequal, narrowed to apex, VI sharply pointed. Tergite 111, 0.3 as long as wide; IV, 0.5 as long as wide: V, 1.25 times wider than long; VI, 0.6 as wide basally as long. Tergites 111 to V each with a transverse row of setae; all tergites finely punctate, I11 to V most densely so.
Color: black except apices of fore femora, bases and apices of fore tibiae and fore tarsi piceous.
Male. Length 1.28 mm. Scape 4.6 times as long as wide, not narrowed as in female; pedicel twice longer than wide, narrower than IV; I11 as long as wide, slightly less than half as long as IV; IV, V, and VI all subequal in length and width, 1.7 to 1.8 times longer than wide, IV slightly notched apically; VII, VIII, and IX all 1.6 times longer than wide, equally long; X, 2.3 times as long as wide, lanceolate as in the female. Abdomen narrower than thorax across tegulae, 0.9 as long as head and thorax united; tergites I11 and IV equally long, 2.5 times longer than V; V and VI subequal, twice longer than VII. Abdomen shining, tergites I11 to VII each with a transverse row of setae and a bare median line.
Color: similar to female.