Mecidea major Sailer 1952
Creators: name: Mcpherson, J. E.
name: Bundy, C. Scott
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Pentatomidae
Mecidea
Mecidea major

description: Key to Nymphal Instars of Mecidea major and M. minor 1
1 Tylus longer than juga; nota without distinct dorsal submedial and sublateral longitudinal stripes; posterior margin of mesonotum almost straight, weakly to not extended posteriorly (Figs. 5 and 12); thoracic pleura brown, without stripes (Figs. 19 and 24); length less than 1.20........................................................................... first instar2
- Tylus longer to shorter than juga; nota with distinct submedial and sublateral longitudinal stripes; posterior margin of mesonotum moderately to strongly extended posteriorly (e.g., Figs. 6–7, 13–14); thoracic pleura usually with one to two longitudinal stripes, one dorsal, one ventral (Figs. 20–23, 25–28); length more than 1.70....................................... 2
2 Medial abdominal plates 1–3 with anterior margin heavily bordered with dark brown except medially (Figs. 6–11); thoracic pleura usually with one longitudinal stripe (dorsal) (Figs. 20–23); body in older instars (3rds–5ths) broadly elongate-oval (Figs. 7– 11) (M. major)..................................................................................... 3
- Medial abdominal plates 1–3 with anterior margin narrowly dark brown except white medially or completely white, heavy brown area confined to lateral/sublateral areas (Figs. 13–18); thoracic pleura generally with two longitudinal stripes, one dorsal, one ventral, but ventral stripe may be absent (Figs. 25–28); body in older instars (3rds–5ths) narrowly elongate-oval (Figs. 14–18) (M. minor).................................................................................... 6
3 Tylus longer than juga (Fig. 6); antennal segment 2 with dorsal surface rounded; mesonotum with posterior margin weakly extended posteriorly, straight laterally (Fig. 6); thoracic pleura usually with longitudinal stripe well developed and unbroken (Fig. 20); lengths, 2.06 ± 0.03 (2.02 ± 0.03); widths, 0.92 ± 0.02 (1.09 ± 0.02)............................second instar
- Tylus subequal to shorter than juga (Figs. 7–11); antennal segment 2 with dorsal surface carinate; mesonotum with posterior margin strongly extended medially, arcuate laterally (Figs. 7–11); thoracic pleura usually with longitudinal stripe usually well developed, but may be broken in lighter forms (Figs. 21–23)................................................... 4
4. Tylus and juga subequal in length, wing pads lacking (Fig. 7); lengths, 3.17 ± 0.07 (3.16 ± 0.06); widths, 1.31 ± 0.01 (1.75 ± 0.04)....................................................................................... third instar
- Tylus shorter than juga, leaving apical notch, wing pads easily discernible (Figs. 8–11).............................. 5
5 Wing pads shorter, reaching abdominal segment 2 (Figs. 8–9); lengths, 4.51 ± 0.15 (4.53 ± 0.15); widths, 2.00 ± 0.04 (2.40 ± 0.09)...................................................................................... fourth instar
- Wing pads longer, reaching abdominal segment 3 or 4 (Figs. 10–11); lengths, 7.62 ± 0.17 (7.78 ± 0.17); widths, 2.92 ± 0.06 (2.99 ± 0.11).................................................................................. fifth instar
6 Tylus and juga subequal in length (Fig. 13); antennal segment 2 with dorsal surface rounded; mesonotum with posterior margin weakly extended medially, nearly straight laterally (Fig. 13); thoracic pleura usually with two well-developed stripes, which are unbroken (Fig. 25); lengths, 1.82 ± 00.8 (1.81 ± 0.08); widths, 0.79 ± 0.02 (0.94 ± 0.03)....................second instar
- Tylus shorter than juga, leaving apical notch shorter than juga (Figs. 14–18); antennal segment 2 with dorsal surface carinate; mesonotum with posterior margin moderately to strongly extended medially, arcuate laterally (Figs. 14–18); thoracic pleura usually with two well-developed stripes, which may be broken in lighter forms (Figs. 26–28)......................... 7
7 Wing pads lacking (Fig. 14); lengths, 3.05 ± 0.05 (3.08 ± 0.05); widths, 1.05 ± 0.02 (1.23 ± 0.04).............. third instar
- Wing pads easily discernible (Figs. 15–18)................................................................. 8
8 Wing pads shorter, reaching abdominal segment 2 (Figs. 15–16); lengths, 4.52 ± 0.12 (4.63 ± 0.12); widths, 1.54 ± 0.02 (1.70 ±0.04)..................................................................................... fourth instar
- Wing pads longer, reaching abdominal segment 3 or 4 (Figs. 17–18); lengths, 6.64 ± 0.16 (6.89 ± 0.16); widths, 2.35 ± 0.02 (2.20 ± 0.05).................................................................................. fifth instar
1 Length was measured from apices of tylus and juga to apex of abdomen (two measurements); width across mesonotum and abdominal segments 3–4, whichever was widest (both measurements shown).
2 First instars of M. major and M. minor cannot be distinguished easily using morphological characters.
description: Published as part of Mcpherson, J. E. & Bundy, C. Scott, 2021, Identification of Nymphal Instars of Mecidea major Sailer and Mecidea minor Ruckes (Hemiptera: Heteroptera: Pentatomidae: Mecideini) fromtheSouthwestern and Central United States, pp. 479-488 in Zootaxa 4958 (1) on pages 480-487, DOI: 10.11646/zootaxa.4958.1.28, http://zenodo.org/record/4692295