MYDIDAE

J. Wilcox & N. Papavero, 1971, The American Genera of Mydidae (Diptera), with the Description of three new Genera and two new Species, Arquivos de Zoologia 21 (2), pp. 41-119 : 76-79

KEY TO THE AMERICAN GENERA OF MYDIDAE

1. Hind metatarsus about five times as long as broad and subequal in length to segments 2-4; postscutellar slopes pilose; palpi slender and about one-half length of oral cavity; ~ with apical circlet of strong spines 2 Hind metatarsus about three times as long as wide and subequal in length to segments 2-3 4

2. Proboscis long and slender, about four times length of oral cavity; veins M1 and M2 separated, M1 ends in R 1 closing posterior cell 1, M2 usually ends in Costa; posterior crossvein absent; antennal segment 1 about four times length of 2; katepimeron pilose; hind femora about eight times as long as wide, hind tibiae cylindrical, with apical bristles; hind trochanters with fine hairs; length 11-19 mm (Chile, Argentina).................................. M itrodetus Gerstaecker Proboscis subequal to length of oral cavity; veins M1 and M'2 combined and ending in Costa with posterior cell 1 open; posterior crossvein present; antennal segment 1 about two times length of 2; katepimeron bare; hind femora six to seven times as long as broad, hind tibiae with ventral keel and usually a spur and bristles; hind trochanters with two to five short strong spines 3

3. Stem of proboscis subequal to length of oral cavity, labella short and slightly wider than stem; submarginal cell 2 usually clos­ ed and short petiolate; hind tibiae with small apical spur and usually several bristles, spur very small or absent in some ~ ~; length 18-25 mm (USA, Mexico) Opomydas Curran

Stem of proboscis about one-half length of oral cavity, attached at middle of labella which is subequal to length of oral cavity; submarginal cell 2 usually broadly open; hind tibiae with api­ cal spur and a bristle at base; length 22-29 mm (USA, Mexi­ co) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 •• 0.0.0.0 •• 0 0 0 0 0. lletero1 nydas Flardy

·40 Second submarginal cell of wings closed, i 0e., vein R5 ends in vein R 1 0 0 •• 0 ••• 0 0. 0 •• 0 0 0 0.00 ••• 0.00.0 •• 0 0 0 •• 0 •••• 0 0 0 •••••• 5 Submarginal cell 2 of wings open, i. e., vein R 5 ends in the costa; stem of proboscis about one-half length of oral cavity, attached to middle of labella which is subequal to length of oral ca- vity. 00 '.0.0. 0 0 0 ••••• 0 ••••••• 0 0 •••• o ••• 0 0 0 0 •• o. •• 12

,'5. Hind femora usually strongly swollen; hind tibiae usually with an apical spur; ~ abdomen with fine hairs at apex 0 •• 0 0 0 6 Hind femora rather slender, six to ten times as long as wide; hind tibiae cylindrical with apical bristles 0 0 0 0 0 ••••••• 0 0 10

;6. Abdomen pedunculate, segment 3 narrow and one and one-half times as long as broad; length 27 mm (Brazil) ... 0 0 •• 0 o ••• ••• 0 0 0 0 0 ••• 0 0 0 0 0 0 0 •••• 0 0 0 0 Ceriornudas Williston Abdominal segment 3 broader than long in dorsal view. 0 0 •• 0 0 7

"7. Stem of proboscis subequal to length of oral cavity, labella attached to apical one-half or more and extending out at about a 90° angle; oral margin opposite the lower eye margin 0 •• 0 •• 0 8 Stem of proboscis about one-half length of oral cavity, attached at middle of labella which is subequal to length of oral cavity; oral margin situated at about two-fifths distance from lower eye margin to antennae ... 0 0 0 0 0 0 0 0 0 0 •••••• 0 0 9

:9. Antennae short, segment 3 widened apically and subequal in length to segments 1-2, club as long as segments 1-3; posterior cross­ vein absent; length 20-27 mm (Brazil, Paraguay). 0 0.0.0 0. •••• 0 0 •• 0 0 0 0 0 0 ••• 0 ••••••• 0 Dolichoqaster Macquart

Antennal segment 3 slender and at least two times as long as seg­ ments 1-2, club shorter than segment 3; posterior crossvein present; length 15-29 mm (N. and S. America) 0 0.0 •• •••••••••••••••• 0 ••• 0 •••••• 0 Messiasia d' Andretta

10. Laterotergite bare; posterior crossvein present; stem of proboscis attached to middle of labella, labella slightly shorter than oral cavity; antennal club longer than segment 3; hind femora about 10 times as long as broad, venter with long hairs and 2-3 subapical spines; ~ with apical hairs; length 12-18 mm (Peru) Piuomudas , gen. n.

Laterotergite pilose, hairs short and inconspicuous in some ~ ~; posterior crossvein absent; proboscis obsolete to functional, varying from about one-half to three times the length of the oral cavity; ~ with apical circlet of spines 11

11. Antennal club shorter than to subequal in length to segment 3; basistylus divided apically, each arm with a single prong; length 9-20 mm (USA, Mexico). ·....................... .. Pseudonomoneura M. Bequaert

Antennal club longer than segment 3; 0' sternite 9 divided basally, each arm with two apical prongs; length 12-23 mm (British Columbia to Panama) Nemomydas Curran

12. Hind femora slender, seven to ten times as long as wide; hind tibiae cylindrical, with apical bristles 13

Hind femora swollen, four to seven times as long as broad; hind tibiae with ventral keel and with apical spur; posterior crossvein present 15

13. Posterior crossvein absent; hind femora with short hairs and seven spines on venter; ~ abdomen with apical circlet of spines; length 10-14 mm (Brazil). ~...... .. Pseudo rhopalia ) gen. n.

Posterior crossvein present 14

14. Submarginal cell 2 open; palpi slender and two-fifths length of oral cavity; hind femora with short hairs and about 15 spines on venter; club of antennae globular, three-fourths as wide as long; ~ with apical circlet of spines; length 14-20 mm (Chile) ·..................................... Midacritus Seguy

Submarginal cell 2 open or closed; palpi short; hind femora with fringe of long hairs on venter and 2-3 subapical spines; club of antennae less than one-half as broad as long; ~ with apical hairs; length 12-18 mm (Peru) Pluomudas , gen. n.

15. Abdomen deeply and densely punctate, ~ with apical hairs; katepimeron pilose; alulae with squamose fringe; axillary lobe as broad as long; length 18-23 mm (Chile). ·...................... Paramydas Carrera & d' Andretta

Abdomen smooth, ~ with apical circlet of spines; katepimeron bare 16

16. Axillary lobe less than one-half as broad as long; alulae with fringe of very short fine hairs; hind femora strongly swollen, 0' four to four and one-half, ~ four and one-half to five, times as long as broad; length 14-19 mm (Chile) .. Apiophora Philippi

Axillary lobe as broad as long; alulae with dense fringe of long squamose hairs; hind femora moderately swollen, 0' six, ~ seven, times as long as broad; length 21-28 mm (Brazil) .......................................... Eumydas J gen. n.