Macrodactylus, Dejean, 1821

Arce-Pérez, Roberto & Morón, Miguel-Angel, 2005, New species and new records of species of Macrodactylus Dejean (Coleoptera: Scarabaeidae: Melolonthinae: Macrodactyini) from Honduras and Nicaragua, Zootaxa 1012 (1012), pp. 23-37 : 24-25

Key to the species of Macrodactylus from Honduras and Nicaragua

In the genus Macrodactylus , males and females can be separated using the following characters: male with pygidium longer than wide, last abdominal sternites slightly concave; female with pygidium as long as wide, last abdominal sternites convex.

1.­ Pronotum and elytra glabrous ....................................................................................... 2

1' Pronotum with scale­like setae at least on the borders. Elytra more or less covered with scale­like setae or short slender setae.................................................................... 3

2.­ Pronotum and elytra orange­yellow ( Figs. 7, 10). Male protibia with acute spine in the middle of inner border ............................................... M. tibialis Arce­Pérez and Morón

2' Pronotum and basal third of elytra orange­yellow, distal two thirds of elytra iridescent black or dark blue ( Fig. 5). Male protibia without acute spine in the middle of inner border .......................................................................... M. dimidiatus Guérin­Méneville

3.­ Elytra with scale­like setae uniformly distributed or arranged in longitudinal rows .... 4

3 Elytra without scale­like setae or with scattered minute slender setae ......................... 7

4.­ Tarsal segments with numerous white, long setae. Elytra completely covered with mustard yellow scale­like setae ( Fig. 8). Male pronotum completely covered with yellow scale­like setae, female pronotum with scale­like setae only near the borders ( Fig. 11). Parameres with lateral setae .............................. M. hondurensis Arce­Pérez and Morón

4' Tarsal segments with sparse, white, short setae or glabrous. Elytra with more or less glabrous longitudinal stripes. Vestiture of pronotum variable. Parameres without lateral setae........................................................................................................................ 5

5.­ Elytra with two well defined longitudinal stripes of scale­like setae on interstriae 1 and 3; interstriae 2 and 4 costate, glabrous. Pronotum black or dark brown with scarce scale­like setae ( Fig. 1) .................................................................... M. costulatus Bates

5' Elytra with one wide longitudinal stripe of scale­like setae along the inner half of disc. Interstriae 2 and 4 not costate. Pronotum black, dark brown, or dark green with dense vestiture of scale­like setae ........................................................................................... 6

6.­ Elytra uniformly reddish­brown ( Fig. 2). External half of the elytral disc with irregularly distributed small, scale­like setae. Scutellum with scattered setae......................... ...................................................................................................... M. sericeicollis Bates

6' Elytra dark brown or black on the posterior half and reddish­brown on the anterior half ( Fig. 4). External half of elytral disc with small scale­like setae arranged in two irregular stripes. Scutellum densely covered with scale­like setae .................. M. suavis Bates

7.­ Elytra orange­yellow with iridescent sericeus shine. Base of each elytron with 5­6 erect, black, long, thick setae. Pronotum iridescent dark green with stripe of yellow scale­like setae along the midline and scattered setae near the borders ( Fig. 6). First segment of male protarsus 1.4 times longer than segments 2 and 3 combined............... ............................................................................................................... M. sylphis Bates

7' Elytra yellow or bicolored. Base of each elytron with or without setae. Pronotum black or dark green. First segment of male protarsus as long as segments 2 and 3 combined8

8.­ Elytra orange­yellow with slight sericeus shine ( Fig. 9). Pronotum black with small setae near the margins. Scutellum with scarce, small setae. Parameres with lateral setae ............................................................................... M. montanus Arce­Pérez and Morón

8' Elytra orange­yellow in the basal half and black in the apical half with a strong iridescent metallic shine ( Fig. 3). Pronotum iridescent dark green with a row of scale­like setae on the basal third of midline and scattered setae near the borders. Scutellum densely covered with yellow scale­like setae. Parameres without lateral setae ............. .......................................................................................................... M. sericinus Bates