A NEW EXOCRINE GLAND IN THE SLAVE RAIDING 
ANT GENUS POLY ERG US 
By Bert HOlldobler* 
Department of Organismic and Evolutionary Biology, 
MCZ-Laboratories, Harvard University, 
Cambridge, Massachusetts 
Introduction 
In his classical study of the workers and males of Myrmica rubra, 
Janet (1898, 1901) discovered a pair of clusters of a few glandular 
cells under the 6th abdominal tergite. Each cell is drained by a duct 
that penetrates the intersegmental membrane between the 6th and 
7th abdominal tergites. Recent investigations have demonstrated 
that this gland is very common in ants, but it varies considerably in 
size and structure (Holldobler and Engel 1978). Since the gland is 
anatomically closely associated with the last exposed tergite in 
female ants (7th abdominal tergite = pygidium) Kugler (1978) sug- 
gested that it be called the pygidial gland. Recently Jessen and 
Maschwitz (1983) proposed the alternative name, Janet’s gland, in 
honor of its discoverer Charles Janet. 
The pygidial gland has been found in workers of representative 
species belonging to all subfamilies except the Formicinae (for liter- 
ature review see Holldobler and Engel 1978; Holldobler and Engel- 
Siegel 1982; Holldobler 1982). 
I report here the first discovery of a pygidial gland in Poiyergus, a 
genus of the subfamily Formicinae. But the anatomy has unusual 
features that point to a possibly indepedent origin in evolution. 
Material and Methods 
Three species of Poiyergus were investigated. The European spe- 
cies Poiyergus rufescens was collected near Wurzburg (W-Ger- 
many), the two North American species P. breviceps and P. lueidus 
were found near Portal (Arizona) and near Rocky Point in Suffolk 
County (New York), respectively. Virgin queens and males were 
* Manuscript received by the editor March 24, 1984. 
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