Myzinum

Key to the North American species of Myzinum

1 Metasoma with 7 visible segments, apical sternum forming slender hook (uncus); antenna 13-segmented, usually held straight, not coiled; body long slender; males....................................................................................................... 2

- Metasoma with 6 visible segments, apical sternum not slender or hook-like; antenna 12-segmented, usually coiled; body robust; females ................................................................................................................................................... 10

2 Forewing marginal cell Rs vein obsolescent or indicated by stained line (Fig. 3); hypostomal angle obtuse in side view; paramere ventral lobe with 3–4 peg-like spines apically (Fig. 7) .................. cocoritensis Kimsey, new species

- Forewing marginal cell Rs vein present (Fig. 6); hypostomal angle forming right or acute angle in side view; paramere ventral lobe with slender spines apically (as in Fig. 8)................................................................................. 3

3 Metasomal tergum VII with medial longitudinal groove or crease (as in Fig. 11).......................................................4

- Metasomal tergum VII flat, without medial longitudinal groove or crease.................................................................. 5

4 Wing membrane evenly brownish yellow; tergum VII usually marked with yellow; volsella flat, apically rounded ... ............................................................................................................................................ quinquecinctum (Fabricius)

- Wing membrane largely hyaline, darkened at tip; tergum VII black, without yellow; volsella triangular in cross-sec- tion, pointed apically .......................................................................................................................carolinanum Panzer

5 Midcoxa dentate, lobate or broadly angulate on inner margin (as in Fig. 5)................................................................ 6

- Midcoxa unmodified..................................................................................................................................................... 7

6 Midcoxa lobate or dentate (Fig. 5); paramere ventral lobe less than 3x as long as broad basally, margin above notch angulate, ventral lobe having spines along apical fourth of length (Fig. 21) ............................... obscurum (Fabricius)

- Midcoxa broadly angulate; paramere 3.5x or greater as long as broad basally, margin above notch linear, ventral lobe having spines along three-fourths of length (Fig. 17) .......................................................................... frontalis Cresson

7 Hindcoxa with small, low tooth on inner margin; paramere ventral lobe with spines extending along more than half length; volsella triangular in cross-section (Fig. 16) ....................................................................... dubiosum (Cresson)

- Hindcoxa without small tooth on inner margin; paramere with ventral lobe spines extending along one-third length or less; volsella various ................................................................................................................................................. 8

8 Paramere medial notch absent, ventral lobe undeveloped, not distinguished from dorsal lobe; volsella as long or nearly as long as paramere ventral lobe (as in Fig. 19); aedeagus not apically bulbous, narrowly enlarged apically, with ventral ridge narrow, not lamellate ....................................................................................................................... 9

- Paramere medial notch deep, clearly separating ventral from dorsal lobe; volsella one-third to one-half as long as paramere ventral lobe; aedeagus apically bulbous, greatly inflated, more than twice as broad as shaft below, ventral ridge broadly lamellate (Fig. 20) ......................................................................................................... navajo Krombein

9 Flagellomere I 1.4–1.6x as long as broad; volsella triangular in cross-section. ......................... maculatum (Fabricius)

- Flagellomere I 1.2–1.3x as long as broad; volsella flat in cross-section ........................................ confluens (Cresson)

10 Forewing marginal cell Rs vein obsolescent or indicated by stained line; hypostomal angle obtuse in side view (Fig. 1) ............................................................................................................................... cocoritensis Kimsey, new species

- Forewing marginal cell Rs vein present (as in Fig. 6); hypostomal angle forming right angle or acute angle in side view (as in Fig. 2) ....................................................................................................................................................... 11

11 Propodeal side smooth, without striae or ridging ....................................................................... carolinianum (Panzer)

- Proodeal side longitudinally or obliquely striate or ridged......................................................................................... 12

12 Pronotal disk with numerous tiny punctures between larger ones across most of surface, accompanied by short bristle-like orange or yellow setae ........................................................................................................ fulviceps (Cameron)

- Pronotal disk without numerous tiny punctures between larger ones or only a few tiny ones anteriorly, with scattered pale or black setae ....................................................................................................................................................... 13

13 Propodeum posteriorly entirely covered with coarse ridges radiating out from petiolar socket ....... navajo Krombein

- Propodeum posteriorly smooth or with weak radiating striae .................................................................................... 14

14 Scutum and scutellum entirely black, without yellow markings; metasomal terga with lateral yellowish, ovoid spots not bands ....................................................................................................................................... obscurum (Fabricius)

- Scutum and scutellum black with yellow markings; one or more metasomal terga with complete or medially broken yellow band ................................................................................................................................................................. 15

15 Antenna pale red; wing membrane yellowish brown; pronotal disk with anterolateral yellow spot and broad posterior band; ocellocular distance about twice as long as interocellar distance; body length 18–22 mm ........................... ............................................................................................................................................ quinquecinctum (Fabricius)

- Antenna brownish red to black; wing membrane untinted; bicolored or infuscate; pronotal disk coloration variable; ocellocular distance usually less than twice as long as interocellar distance; body length less than 18 mm ............. 16

16 Forewing with costal margin dark, infumate, rest of wing untinted; pronotal disk beyond anterior margin at least partly bipunctate unless punctures confluent .............................................................................. maculatum (Fabricius)

- Forewing entirely hyaline or uniformly infuscate; pronotal disk usually not bipunctate beyond anterior margin .... 17

17 Metasomal terga I–V with anterior and posterior transverse yellow bands ................................... confluens (Cresson)

- Metasomal terga I–V only with anterior transverse yellow band or lateral spots ...................................................... 18

18 Wings hyaline ...................................................................................................................................... frontalis Cresson

- Wings brown-tinted, at least along costal margin .............................................................................. dubiosum Cresson