FIELD BOOK OF INSECTS. 



of nearly equal length ; scapes and legs without erect hairs. 

 "This ant, which passes in much of our entomological 

 literature as L. alienus, is not only the commonest of our 

 numerous species of Lasius, but the most abundant of 

 our ants, and hence, of all our insects. It occurs over the 

 whole of North America, except the extreme southern and 

 southwestern portions, from timberline on the highest 

 mountains to the sands of seashore. Even in circum- 

 scribed localities it shows, in its nesting sites, great adapt- 

 ability to different physical conditions, from the damp 

 rotten wood of dense forests to the sandy soil of dry, sunny 

 roads. Usually the workers living in the latter stations 

 are much paler in color than the woodland forms. The 

 nests are indifferently under bark, logs, or stones, in rotten 

 wood or in soil. When in the open soil, they are sur- 

 mounted by small single or clustered craters. Like all 

 of our other species of Lasius, L. niger var. americanus 

 is much given to cultivating root aphids in the chambers 

 and galleries of its nests; but, with the exception of the 

 variety neoniger [scapes and legs beset with erect hairs], 

 it is the only one of our forms that is not exclusively sub- 

 terranean in its habits." 



A few of the species of Formica may be separated as 

 follows : 



1. Clypeus with a notch in middle of anterior border. 

 F. sanguinea; var. subintegra is light red, with brown 

 gaster, and var. nibicunda, among others, is deep red, with 

 black gaster. 



Clypeus without such notch 2. 



2. Posterior border of head broadly excised 



F. exsectoidcs. 

 Posterior border of head not excised 3. 



3. Body rather stout; head of larger workers usually 

 but little longer than broad; second to third funicular 

 joints much more elongated than sixth to eighth; color red, 

 with brown or black gaster 4. 



Body more slender and graceful; head of larger 

 workers distinctly longer than broad; second to third 

 funicular joints but little more elongated than sixth to 

 eighth; color rarely as in preceding 5. 



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