Vol. VI. May, 1904. No. 6 



BIOLOGICAL BULLETIN 



A CRUSTACEAN-EATING ANT (LEPTOGENYS ELON- 



GATA BUCKLEY). 



WILLIAM MORTON WHEELER. 



There are few more profitable fields for the comparative study of 

 instinct than the larger genera of the social Hymenoptera. This 

 is especially true of the larger genera of ants, such as Cauipo- 

 notns, Formica, Myniiccocystns, Lcptotliora.v, Plicidolc, Atta and 

 Crematogaster. To these genera, each of which embraces species 

 presenting a considerable range of ethological peculiarities while 

 differing but little in morphological characters, we must also add 

 Leptogenys, with its subgenus Lobopelta, a rather large tropico- 

 politan congeries of species belonging to the primitive Ponerine 

 subfamily. 1 



Only a single member of this genus, Lcptogcnys (Lobopcltd] 

 clongata Buckley, is known to occur north of the Rio Grande 

 River. It is not uncommon in the semiarid regions of Central 

 Texas (Travis and Comal counties) and has been taken even as 

 far north as Colorado and the District of Columbia. Frequent 

 observations during the past three years have enabled me to 

 confirm and extend my former account of the habits of this very 

 interesting ant. 2 



I am now able to state positively that the peculiar apterous 

 females, indistinguishable from the workers except for the shorter 

 and more rounded petiolar node and the more voluminous gaster, 

 are the only females produced in the colonies of L. clongata. 

 Each colony contains only a single one of these females and no 

 other is tolerated in the nest. Even the young virgin females 

 leave the formicary very soon after hatching and acquiring their 



1 Lobopclta differs from Leptogenys sensu stricto in having broader mandibles which, 

 when closed, leave little or no space between their inner borders and the anterior 

 margin of the clypeus. 



2 " A Study of Some Texan Ponerinx," Bioi.. BULL., Vol. II., No. i, Oct., 1900. 



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