THE CANADIAN ENTOMOLOGIST . 237 



NOTES ON THE NORTH AND CENTRAL AMERICAN 



SPECIES OF ACANTHOCEPHALA LAP. 



(Earn. Coreidse: Heteroptera.) 



BY EDMUND H. GIBSON AND ABBY HOLDRIDGE, U. S. BUREAU 

 OF ENTOMOLOGY, WASHINGTON, D. C. 



An exceptionally good and large series of specimens of the 

 genus Acanthocephala Lap. in the collection of the U. S. National 

 Museum has afforded the writers an opportunity for detailed 

 study of this group, and has enabled them to untangle several of 

 the perplexing questions in regard to the identity of species. 



Acanthocephala is a neotropical genus and contains a rather 

 long list of described species. However, it seems warranted to 

 believe that with further study of South American material the 

 number of species will be reduced as many will probably be forced 

 into synonymy. Seven species are known to occur in Central 

 America, five of which are also to be found in southern United 

 States. 



Previous workers have divided the genus into two subgenera, 

 according to the variation in the form and shape of the thorax, 

 but as this character exhibits great variability within a species and 

 the forrn and the shape of the dilatation of the hind tibia is cer- 

 tainly of more value in separating the species and is constant 

 within a species, the present authors feel justified in not recog- 

 nizing the old subgeneric divisions and are even restrained from 

 forming new ones. 



Acanthocephala was described by Laporte in 1832, Ess. Hem., 

 p. 29, and may be characterized as follows: 



Head short, terminating in a spine as viewed from above. 

 Antenna long and slender, first joint stouter than the rest and 

 slightly longer than the length of the head, fourth joint usually 

 somewhat curved. Thorax wider than elytra. Membrane ex- 

 tending slightly beyond apex of abdomen. Posterior femora more 

 or less swollen, sometimes greatly so and curved, armed with 

 prominent spines. 



Posterior tibia with dilatations on either side, the outer 

 dilatation the widest and longest. 



It is the largest and best known genus of the tribe Acantho- 

 cephalini Stal. The orthotype of the genus is latipes Drury. 



July, 1918 



