Key to the species of Plagiohammus

1. Elytra densely ochre-yellow pubescent, with small black dots P. pollinosus (Bates) (Fig. 44)

— Above at least indistinctly maculate, either on elytra or on pronotum ..................................... 2

2(1). Elytra nearly uniformly white tomentose .......................... P. imperator (Thomson) (Fig. 35)

— Elytra not largely white................................................................................................................ 3

3(2). Elytra white with small black maculae .................................... P. niveus (Breuning) (Fig. 36)

— Elytra without black maculae ...................................................................................................... 4

4(3). Elytral maculation consisting of denser patches of the same pubescence as that covering the entire upper surface; Elytra light fulvous tomentose, macula very numerous, vague and small; elytral apices strongly spined at tip, maculae pinkish ............................................................... ....................................................................................................................................................... ................................................................................. P. confuso r Dillon and Dillon (Fig. 39)

— Elytral maculae more or less contrasting to rest of pubescence ................................................ 5

5(4). Elytra light fulvous tomentose, macula very numerous, vague and small; elytral apices strongly spined at tip, maculae pinkish............................... P. confuso r Dillon and Dillon (Fig. 39)

— Elytra with visible pores throughout........................................................................................... 6

6(5). Elytra with light brown maculae, apices without spine ............ P. sallei (Thomson) (Fig. 40)

— Elytra polished black, with numerous transverse spots of different color ................................ 7

7(6). Maculae light brown with elytral apices strongly spiny................................................................ ....................................................................................................................................................... ................................................................................. P. camillus Dillon and Dillon (Fig. 38)

— Maculae differently colored .......................................................................................................... 8

8(7). Maculae with irregular pinkish spots; elytral apices unarmed ........ P. sargi (Bates) (Fig. 32)

— Elytral apices strongly spiny at tip.............................................................................................. 9

9(8). Elytra with four irregular chalk-white maculae, and few small dots ........................................... ....................................................................................................................................................... ................................................................................................ P. thoracicus (White) (Fig. 29)

— Maculae chalk-white with many small dots .............................................................................. 10

10(9). Maculae of elytra yellowish-white, at least five large and very irregular; elytral apices shortly spine; beneath laterally yellowish-white maculate ................... P. ornator (Bates) (Fig. 43)

— Pubescence of elytra (except of maculae) in minute, reticulating patches .............................. 11

11(10). Elytra with four large white spots, with minute dots throughout P. nitidus (Bates) (Fig. 27)

— Elytra black without small spots ............................................................................................... 12

12(11). Four regular maculae of elytra chalk-white, beneath later immaculate, reticulating patches brown ..................................................................... P. olivescens Dillon and Dillon (Fig. 31)

— Four regular maculae of elytra yellowish.................................................................................. 13

13(12). White elytra spots fused in the middle forming a half-circle ....... P. lunaris (Bates) (Fig. 41)

— Spots not fused in the middle ..................................................................................................... 14

14(13). Elytra nearly uniformly brown tomentose ................................ P. blairi (Breuning) (Fig. 37)

— Elytra with yellowish, white or orange ochraceous spots......................................................... 15

15(14). Elytra with five orange ochraceous spots ................................ P. rubefactus (Bates) (Fig. 16)

— Elytra with white spots, extreme base of elytra immaculate ................................................... 16

16(15). Elytra with three large white spots ............................................... P. albatus (Bates) (Fig. 24)

— Elytra with four white medium size spots................................................................................. 17

17(16). Elytra with two yellowish maculae; elytra brown tomentose........................................................ ................................................................................ P. brunneus Dillon and Dillon (Fig. 34)

— Elytral maculae white, usually more abundant; elytra brown tomentose .............................. 18

18(17). Pronotum only feebly transversely rugose; each elytron with three to four white maculae ....... ............................................................................ P. spinipennis (Thomson) (Fig. 23, 54, 55)

— Elytra with five to six medium size maculae............................................................................. 19

19(18). Lunule of elytra ashy; elytra unarmed at apex, beneath immaculate.......................................... ............................................................................................... P. granulosus (Bates) (Fig. 26)

— Lunule of elytra white ................................................................................................................ 20

20(19). Elytra dark brown, uniform, clean white spots on sternite rounded and smal........................... l ............................................................................................. P. elatus (Bates) (Fig. 19, 50, 51)

— Elytra black with small brown-grayish maculae ...................................................................... 21

21(20). Elytra with white irregular spots, immaculate at base and apex................................................. ................................................................................................... P. laceratus (Bates) (Fig. 33)

— Elytra with yellow irregular spots ............................................................................................. 22

22(21). Elytra with six regular yellowish spots; elytra dark brown .... P. maculosus (Bates) (Fig. 22)

— Pubescence of elytra (except of maculae) in minute, reticulating patches .............................. 23

23(22). Two large irregular white spots fused in the middle; minute brown dots scattered between the white spots ........................................................ P. decorus Chemsak and Linsley (Fig. 25)

— Elytra with five or six large irregular spots contrasting to rest of pubescence....................... 24

24(23). Elytral apices unarmed, four basal grayish-white dots, spots more distinctly lateral ................ ........................................................................................ P. lacordairei (Thomson) (Fig. 42)

— Elytral apices armed ................................................................................................................... 25

25(24). Maculae sulfur yellow, with many small dots; elytra polished purplish brown........................... .............................................................................. P. emanon Dillon and Dillon (Fig.17,18)

— Elytra brown, maculated at base and apex ............................................................................... 26

26(25). Maculae mustard yellow in females, or whitish-yellow in males with four large ovate spots; elytra dark brown .............................................................. P. thiodes (Bates) (Fig. 20,21, 47)

— Maculae white, elytra black or reddish ochre ........................................................................... 27

27(26). Maculae golden yellow, with six large irregular spots; elytra grayish-brown with many small golden yellow dots covering the elytra.......................... P. colombiensis n. sp. (Fig. 1, 2, 15)

— Elytra with white spots .............................................................................................................. 28

28(27). Elytra reddish-ochre with several small white dots .................... P. sticticus (Bates) (Fig. 28)

— Elytra black with few large white spots .................................................................................... 29

29(28). Elytra very densely dotted with white throughout, each elytron with large white spot forming two transverse bands, one situated a little before the middle, the other at the beginning of the apical third...................................................... P. mexicanus Breuning (not illustrated)

— Elytra light brown with five large white dots; white small dots absent ....................................... ................................................................................................ P. inermis (Thomson) (Fig.30)