5-7-1951 — M. A. V. D'Andretta — Contrib. sôbre a família Mydaidae 
15 - Alxlominal tergites with greoii metallic reflectioiis 
laterally and black spots in the lateral margins; 
wings byaline. 
- Abdominal tergites without green reflections; 
wings witli tbc veins of the anterior margin bord- 
ered with brown. 
16 - Abdômen almost intirely black, the yellow batul 
of the posterior margin of the tergite reduced 
and only present laterally. 
- Abdômen witli conspicuous transversal yellow 
bands, at least in some tergites .... 
17 - All abdominal tergites yellow in the posterior 
margin; posterior femora normally thick . 
- Only the third, fonrth and fifth abdominal ter¬ 
gites yellow in the posterior margin; posterior 
*femora very thick. 
18 - Post-scutellar region with two rounded wbitish 
spots; mesonotum with fottr median longitudinal 
vittae of white pollen; first abdominal -segment 
with whitish pile. 
- Post-scutellar region without rounded whitish 
spots; lateral margins of the mesonotum orange, 
without median logitudinal vittae; first abdomi¬ 
nal segment with dark pile. 
militar is Gerstaecker 
rufiventris Macquart 
qnadrilineutus Williston 
17 
18 
interruptns Wiedemann 
gracitis Macquart 
basalis Westwood 
Tt was not possible to include in this key the following species: nitiduhts 
Olivier, 1811, virgatu.; Wiedemann, 1829, tricolor Wiedemann, 1829, submtcr- 
ruptus Bcllardi, 1861, bitaeniafus Bellardi, 1861, cmnularis Gerstaecker, 1868, 
cleptes Oslen Sacken, 1886, claripcnnis Williston, 1897, and ctlpolis Séguy, 1928. 
Mydns chrysites Osten Sacketi, 1886, as figured by Séguy (1928) has a crowii 
of spines in the female genitalia, and so it does not belongs to Afyda-t. 
The species of Messiasia, n. gen. may be separated as follows: 
1 - Abdômen black with or without blue or green 
metallic reflections.2 
- Abdômen dark brown with yellow band in the 
posterior margin of each segment, or orange-yel- 
lowish with dark brown s]>ots.4 
2 - Abdômen wholly black without metallic reflections 
- Abdômen with intense blue or green metallic re¬ 
flections . 
3 - Abdômen with a yellow spot on the second tergite 
and sternite . ■ 
- Abdômen without such yellow spots . . . , 
(Osten Sacken) 
sikani, n. sp. 
poli ta (Wiedemann) 
cm l 
; SciELO 
10 11 12 13 14 
