THE NEARCTIC SPECIES OF IPHITRACHELUS WALKER (HYMENOPTERA, PROCTOTRUPOIDEA, PLATYGASTRIDAE), WITH A KEY TO WORLD SPECIES

Abstract The three species of Iphitrachelus in America north of Mexico are reviewed. I. canadensis n. sp, is described from Ontario, Quebec, and Newfoundland. A key to all known species is given. The world distribution of Iphitrachelus is discussed.


Iphitrachelus foutsi Jackson
Iphitrachelusfoutsi Jackson, 1966, Proc. ent. Soc. Wash. 68: 265-267. Described originally from a single female from Maryland, it has turned out to be a very widely spread but rare species. So far as is known it is confined to the Western Hemisphere. There is a closely related undescribed species in Trinidad, W.I., and Brazil differing from foutsi mainly in having the two foamy scales on tergite 1 confluent.
The three males in our material represent the first known males of I. foutsi. They
Length 0.8 mm. Dark chestnut brown, petiole reddish brown, antennae and legs including coxae uniformly dirty yellow; foamy membranes on propodeum, metasternum and petiole whitish; wings almost clear.
Head transverse, almost twice as wide as long, strongly reticulate except for clypeal declivity which is smooth and very shiny (Fig. 6). Lateral ocelli very close to inner orbits, distant from them by less than their own diameter, i.e. very far from the median ocellus. Scape with reticulation similar to that of frons, lower lamella rather wide, narrower than maximum width of scape (3:5), upper apical lamella reduced to an almost inconspicuous strip. Antenna1 segments 2-4 subequal, elongate, with proportionate lengths 5:7:6, segments 5-7 minuscule, triangular, slightly longer than wide, clava distinctly sausage-like, elongate, 3.7 times as long as wide. All antenna1 segments including scape and clava with scattered erect bristles.
Mesosoma with similar but somewhat finer reticulation as on head; however, parts of mesosoma without sculpture, smooth and highly shiny, notably anterolateral parts of pronotum, notauli, scutellar pit, mesopleura (including declivity), mesosternum, and metapleurae. Notauli distinctly dilated posteriorly and separated here by mere point of mesoscutum. Propodeal membrane thick, foamy, not transparent but appearing bubbly reticulate in both dorsal (Fig. 4) and, particularly, lateral aspects. Fore wings broadly rounded and not truncate at apices.
Tergite 1 with pair of reniform foamy scales confluent anteriorly and narrowly separated from here to the end (Fig. 5). Sternite 1 with small foamy membrane. Tergite 2 with 2 longitudinal keels anteriorly and two shallow depressions anterolaterally. Laterotergites of tergite 2 very wide, not appressed to sternite 2 which is, therefore, concealed from the sides but visible from belbw. Male allotype on card point, well preserved (Canadian National Collection, Ottawa, No. 13952); same data as holotype. Differing from female only in antennal characters. Antennae 10-segmented, segments 2-10 very similar to those in 1. lar but segment 4 distinctly shorter and stouter and segment 6 with apical neck-like constriction longer than in I.