PROCEEDINGS 



OF THE 



CALIFORNIA ACADEMY OF SCIENCES 



Fourth Series 



Vol. XI, No. 13, pp. 145-152 October 15, 1921 



XIII 



A STUDY OF NORTH AMERICAN GRASS-BUGS 

 OF THE GENUS IRBISIA 



BY 

 EDWARD P. VAN DUZEE 



Curator, Department of Entomology 



Four species of Irbisia have heretofore been reported from 

 North America: sericans Stal, from Alaska; brachycerus 

 Uhler, from Colorado; solani Heidemann, from California; 

 and mollipes Van Duzee, from California. Six new forms 

 are now added, making ten known species, for the separation 

 of which a key is appended. 



1. Irbisia castanipes, new species 



Surface dull black, less polished than in most of our 

 species; vestiture pale, rather long, appressed; legs uni- 

 formly castaneous; dextral male clasper long. Length 6 mm. 



Head oblique, its length beyond eye one-third greater than greatest length 

 of eye; vertex flattened; temporal areas conspicuous, shagreened ; antennal 

 segment II three times length of I, III and IV equal. Pronotum transversely 

 rugose or obscurely punctate, the callosities small, shagreened ; scutellum 

 minutely transversely wrinkled; elytral punctures obscure. Vestiture very 

 minute and sparse, cinereus; sides of pronotum with a few longer erect pale 

 hairs anteriorly. Rostrum reaching apex of intermediate coxas; lower surface 

 polished. Sinistral clasper of male rather narrow, broadly curved, the sub- 

 acute apex straight; dextral clasper short, little exceeding ventral apex of 

 genital segment. 



Color, opaque bronze-black above and on sides of pronotum; beneath deep 

 polished black; legs castaneous, the femora and tarsi usually darker; apex 

 of coxa: and base of trochanters pale; anterior margin of intermediate and 

 posterior coxal cavities and the orifices polished ivory white. 



