59.57,96 L (7) 



Article XX.— THE NORTH AMERICAN ANTS OF THE GENUS 



LIOMETOPUM. 



By William Morton Wheeler. 



The soft, velvety ants of the remarkable Dolichoderine genus 

 Liometopum Mayr appear to be confined to the south temperate por- 

 tions of the northern hemisphere. So far as known, Europe, Asia, 

 and North America each has a characteristic species. The large 

 male of the European form, L. microcephalum, was described more 

 than a century ago by Panzer ^ although the corresponding worker 

 form was not discovered till more than fifty years later by Mavr.^ 

 This author was also the first to publish a brief description of the 

 worker of our American species, L. apiculatum, from specimens 

 collected in Mexico by Professor Bilimek.^ 



In 1894 Emery ^ described some Calif ornian specimens as a new 

 variety {occidentale) of the European microcephalum, but, as I shall 

 endeavor to show, this form had best be regarded as a variety of 

 apiculatum. More recently Forel has described a third species from 

 Assam as L. lindgreeni} 



In addition to these three living species four fossil forms have been 

 recorded from the Tertiary of Europe and North America: L. an- 

 tiquum Mayr, im-hof/i Heer, and L. schmidti Heer from Radoboj,^ and 

 L. pingue Scudder from White River, Utah, and Green River, Wy- 

 oming.^ These species, however, were all described from imper- 

 fectly preserved male and female specimens more or less dubiously 

 referable to the genus Licnnetopum,. 



During my myrmecological excursions into the southwestern 

 States and Territories I have frequently met with our American 

 Liometopum and have been able to learn something of its habits. 

 Specimens of these ants from a number of localities have been ac- 

 cumulating in my collection till it seems to me to be possible to form 

 a better conception of the geographical distribution of the species. 



'■ Fauna Insect. German., V, 1798, P. 54, T. 2. 



' Beschreibung einiger neuer Ameisen. Verhand. zool. bot. Ver. Wien, Bd. II, 1852, p. 144. 



^ Neue Formiciden. Verhand. zool. bot. Gesell. Wien, XX, 1870, p. 961. 



* Beitrage ziir Kenntniss der nordamerikanischen Ameisenfauna. Zool. Jahrb. Abth. f. Syst., 

 VIII, pp. 330, 33:. 



' Varietes Myrmecologiques. Ann. Soc. Ent. Belgique, Tome XLVI, 1002, p. 293. 



" Vorlaufige Studien uber die Radoboi -Formiciden. Jahrb. k. k. geolog. Reichsanst., 1867, 

 XVII, pp. 57-61. Taf. I. 



' On the First Discovered Traces of Fossil Insects in the American Tertiaries. Bull. U. S. 

 Geol. Surv. Terr., Ill, 1877, p. 742; The Tertiary Insects of North America. U. S. Geol. Surv. 

 Terr., 1890, p. 617. 



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