Iridomyrmex sericeus Mayr 1866:498. Syntype workers: Mexico , in pseudobulbs of Schomburgkia tibicinus ( Heller ) [ NHMW ] (examined).
Liometopum instabile (F. Smith) (part): Mayr 1878:870.
Azteca sericea Mayr : Emery 1893:134.
Azteca instabilis var. mexicana Emery , 1896a:3 [n. nov. for Iridomyrmex xanthochrous Mayr 1866:497 (not Roger 1863)]. Syntype workers: Mexico ( Norton ) [ NHMW ] (examined). NEW SYNONYMY .
The history of the name mexicana is complicated. Roger (1863) described A. xanthochroa based on a single queen from Mexico. Mayr (1866) described workers from Mexico as the workers of xanthochroa . Emery (1893) examined these workers, identifying them as xanthochroa and making xanthochroa a variety of instabilis . Emery (1896a), having discovered that xanthochroa was a species distinct from instabilis , reidentified these same workers as a new variety, instabilis var. mexicana . In the Mayr collection, under " instabilis Sm. var. xanthochroa Rog. ," are several pins with Emery determination labels. The only Mexican material among these are two workers, with labels "Mex, Norton," identified by Emery as " A. instabilis var. xanthochroa ." These are the syntypes of mexicana , and when I examined them I added red labels stating " syntypus Az. mexicana Emery 1896, det. J. Longino 1990." I compared the workers directly with the types of A. sericea .
To confuse matters, a series labeled "Mexico, No. 211," with red type labels indicating they are types of instabilis mexicana has been distributed to American museums. Specimens from LACM have an additional label indicating they are from the Pergande collection. I have examined specimens of this series from MCZC and LACM; and AMNH type labels on the MCZC material suggest there is also material at AMNH. These are not syntypes of mexicana . I identify them as A. pittieri .
Iridomyrmex sericeus, Mayr , Sitzungsber. Akad. Wiss. Wien, liii. p. 498, fig. 8 ([[ worker ]]) (1866) 1. Azteca sericea, Emery , in litt. 2; Dalla Torre, Cat. Hymen, vii. p. 164 3.
xanthochroa, Forel , Bull. Soc. Vaud. Sci. Nat. (2) xv. p. 384, t. 23. fig. 8 (1878) 4 (nec Roger).
Hab. Mexique 1 3; Guatemala, San Felipe (Stoll).
