1988] 
Heinze & Buschinger — Leptothorax 
311 
phic females and more or less workerlike, wingless queens, called 
intermorphs. Intermorphic queens most probably are of the geno- 
type Ee and EE, whereas gynomorphs are always ee (Heinze and 
Buschinger, in prep.). 
The small size of colonies and the ease of rearing them in the 
laboratory make Leptothorax spec. A an ideal ant for studies on 
colony and population structure and colony foundation behavior 
related to functional monogyny. 
During our studies on L. spec. A we have gathered much data on 
the occurrence of polygyny in additional North American species of 
the subgenus Leptothorax s. str. M. R. Smith (= Mychothorax 
Ruzsky). In this paper we present field data and results of labora- 
tory experiments concerning the colony structure of Leptothorax 
spec. A as well as field data on related species. In addition we 
summarize information on mono- and polygyny in some palaearctic 
Leptothorax. 
Methods and Material 
A total of 272 complete colonies of Leptothorax spec. A were 
collected in June 1983, 1985, and 1988 in Quebec (Tadoussac, La 
Baie, Laurentides). More than 250 additional colonies were 
gathered since 1979 in Quebec and adjacent areas of Ontario and 
Northern New England (Me.: Bar Harbor, Baxter State Park; N.H.: 
Mt. Monadnock). Some dozen colonies were kept alive for several 
breeding cycles under artificially shortened annual rhythms (Busch- 
inger, 1974b), in the laboratory at TH Darmstadt, and for several 
months at room temperature in the MCZ labs in Cambridge. 
Other Leptothorax, most living sympatrically with L. spec. A, 
were collected: L. retractus (Que.: Rouyn-Noranda; Alta.: Jasper, 
Banff), the presently undescribed L. spec. B (Que.: Tadoussac, La 
Baie, Laurentides; N.H.: Mt. Monadnock), L. spec. C (Alta.: 
Jasper, Banff, Kananaskis; B.C.: Yoho N.P.), and a Leptothorax 
species similar to L. spec. B (B.C.: Sutton Pass, Mt. Seymour, Man- 
ning Provincial Park). 
Dissections of females and workers were carried out as described 
by Buschinger and Alloway (1978). Instead of killing the females by 
using acetic acid ethyl ether or ethanol, water with a drop of deter- 
gent was used in most cases, because it kills small ants faster than 
