Identification key modified from Bolton [4]

To identify the species in the schulzi group described in this study, the following adaptation to the “Key to Neotropical Pyramica species ” [4] is presented below. Starting from step 39 of the mentioned key, the following couplets were added.

39 ′ Cephalic dorsum just in front of occipital margin with a transverse row of 6 small setae that are only marginally longer and more erect than the ground pilosity. Pronotal humeral setae very short, remiform. Lower mesopleuron smooth (Figure 7 A) .................... ................................................................................................................................ Strumigenys metrix

39 ′′ Cephalic dorsum just in front of occipital margin with a conspicuous transverse row of 4–6 erect hairs that are obviously much longer and more erect than the ground pilosity. Pronotal humeral setae elongate, flattened or truncated apically. Lower mesopleuron entirely reticulate (Figure 7 B).. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ......40

40 ′ Vertex with abundant erect setae, without ground pilosity contrasting to the stand pilosity. Simple erect hairs on mesonotum conspicuously differentiated from the very sparse ground pilosity (Figure 8 A)...... ... ... ..... ..... ... ... ... ... ... .... Strumigenys itannae sp. nov.

40 ′′ Vertex without abundant erect setae. Erect hairs on the mesonotum and spatulate, without significant differentiation from the sparse ground pilosity (Figure 8 B).. ............41

41 ′ First gastral tergite entirely covered on thin striation, basigastral costulae very short and inconspicuous. Mesonotum with two pairs of erect setae (Figure 9 A) ..... ... ... ... ... ...... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ....... ... ... ... ... .... Strumigenys xoko sp. nov.

41 ′′ Except for basigastral costulae, first gastral tergite either entirely smooth or with thin striation on its basal half; basigastral costulae short and inconspicuous. Mesonotum with a single pair of erect setae ... 42

42 ′ First gastral tergite with thin striation on its basal half, basigastral costulae adjunct and inconspicuous, merged with striation (Figure 9 B). Mesonotum with a single pair of erect hairs.. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...... Strumigenys orchibia

42 ′′ Gaster smooth, except for basigastral costulae, which are short, sharply defined and distinctly separated. Mesonotum with 2–3 pairs of erect hairs ............................ 43

43 ′ Petiole node in dorsal view broader than long.. ... ... ... ... ... .... Strumigenys schulzi

43 ′′ Petiole node in dorsal view longer than broad.. ... ... ... ... .... Strumigenys castanea