Key to Lasius queens

This key to queens is based on: Wilson, E. O. 1955. A monographic revision of the ant genus Lasius. Bulletin of the Museum of Comparative Zoology. 113:1-201.

Since this key is from 1955 it should be used with the caution. There are numberous species that are not included here, including the North American Acanthomyops. In 1955 Wilson noted: Excluding the rare Himalayan species return to Lasius alienoflavus (see key to workers).

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Lasius (this genus page provides links to other Lasius keys).

1

 * Metapleural gland opening provided with conspicuous guard hairs; in side view the scutum does not overhang the pronotum but shares with it the anterior thoracic convexity . . . . . 2


 * Metapleural gland opening lacking guard hairs; in side view the scutum overhangs the pronotum and claims all of the anterior thoracic convexity . . . . . 22

2
return to couplet #1
 * HW distinctly less than the width of the thorax just anterior to the regulae . . . . . 3


 * HW about the same as or greater than the width of the thorax just anterior to the regulae . . . . . 13

3
return to couplet #2
 * Length of terminal segment of maxillary palp exeeeding 0.1 X the HW, even if only slightly . . . . . 4


 * Length of terminal segment of maxillary palp less, than 0.1 X the HW, even if by only a slight amount . . . . . 10

4
return to couplet #3
 * When viewed with mandibles opened and the head held in perfect full face (at maximum head length and with the occipital and anterior clypeal borders horizontally aligned), the median third of the anterior border of the median clypeal lobe is flat or emarginate; all the queens of a nest series with at least one and often two or three offset teeth present on the basal angle and along the basal border of the mandible (North America) . . . . . Lasius pallitarsis


 * When viewed as above, the median third of the anterior border of the median clypeal lobe convex or angulate, never flat or emarginate; the posterior basal tooth, with rare exceptions, always aligned with the adjacent teeth of the masticatory border; when it is offset, this condition occurs in a minority of the individuals of the nest series and usually only on one mandible in any individual, and secondary offset teeth are never present on the basal border . . . . . 5

5
return to couplet #4
 * When viewed with the mandibles opened and the head held in perfect full face, the anterior border of the median clypeal lobe is angulate, with two straight or very feebly convex sides meeting in a blunt point at the midline; in a large part of any nest series the penultimate basal tooth is distinctly reduced in size relative to the two flanking teeth (North American species only) . . . . . 6


 * When viewed as above, the anterior border of the median clypeal lobe is broadly and evenly rounded; with rare exceptions the penultimate basal tooth is about the same size as the two flanking teeth . . . . . 7

6
return to couplet #5
 * Scapes and tibiae with numerous standing hairs . . . . . Lasius neoniger


 * Scapes and tibiae lacking 'standing hairs . . . . . Lasius crypticus and . . . . . Lasius sitiens

7
return to couplet #5
 * Length of terminal segment of maxillary palp 0.32-0.34 mm. in the several series measured (Japan) . . . . . Lasius productus


 * Length of terminal segment of maxillary palp not exceeding 0.26 mm . . . . . 8

8
return to couplet #7
 * Scape with numerous standing hairs . . . . . Lasius niger


 * Scape with few or no standing hairs, although decumbent hairs may be numerous . . . . . 9

9
return to couplet #8
 * Scape with numerous decumbent hairs outstanding above the pubescence . . . . . Lasius emarginatus


 * Scape with few or no decumbent hairs outstanding above the pubescence . . . . . Lasius alienus and . . . . . Lasius brunneus

10
return to couplet #3
 * Scape with numerous standing hairs (eastern Asia) . . . . . Lasius talpa


 * Scape with few or no standing hairs . . . . . 11

11
return to couplet #10
 * Tibiae with numerous standing hairs (western U.S.) . . . . . Lasius fallax


 * Tibiae with few or no standing hairs . . . . . 12

12
return to couplet #11
 * Terminal segment of maxillary palp usually longer than the penultimate (see diagnosis) (eastern North America to Wyoming) . . . . . Lasius nearcticus


 * Terminal segment not exceeding in length the penultimate segment (Holarctic) . . . . . Lasius flavus