134 THE CANADIAN ENTOMOLOGIST. 



tarsi white with terminal joint black, posterior tarsi with terminal joint 

 black, base of first white, remainder piceous ; wings faintly clouded, 

 stigma, except white spot at base, and nervures black. Abdomen opaque, 

 with first segment suddenly widened and sides subparallel beyond 

 spiracles, basal segments rugulose, with margins polished, becoming 

 smoother toward apex ; ovipositor as long as body, rufous, sheaths black. 

 Male. — Length 17 to 20 mm.; expanse of wings 24 mm. Differs from 

 female in having antennse entirely black and more slender, and the anterior 

 tibiae have a white line externally. 



Described from 4? and 2 (^ captured at intervals since 1878 on 

 fences, bridges, etc. 



This species looks very much like X. siigtnapterus, Say (and a specimen 

 was so determined for me by Provancher), but is abundantly distinct by 

 its stouter abdomen and differently coloured tarsi, and its more robust 

 and opaque appearance. 



The American species may be tabulated as follows : — 

 Prothorax above with lateral tubercles ; 



Wings with a fuscous band X. atistralis, Cress. 



Wings hyaline, legs black X. Riley i, Ashra. 



Wings hyaline, legs partly red X. humeralis. Say. 



Prothorax above without tubercles \ 



Abdomen with lateral white spots X. albopidus, Cress. 



Abdomen with tips of segments white X. insuiaris, Cress. 



Abdomen entirely black. 



Legs entirely black X. cincticornis^ Cress. 



Legs black and white. 



First segment of abdomen slender... X stigmapteriis, Say. 

 First segment of abdomen stout . . . .X. canadensis^ n. sp. 



Legs ferrugineous X. frigidus, Cress. 



Abdomen rufous, 



Pleura red X. pulcher, Ashm. 



Pleura black X. calidus, Prov. 



Uniformly ferrugineous X. caiifornicus, Cress. 



Obscure rufous, legs black. ,, X. Jloridanus, Ashm. 



The following are the species recorded from Canada : albopictns 

 (Ont. and Que.), calidus (0\Xa.\\a),frigidt(s (Hud. Bay), humeralis (Ont. 

 and Que.), i?isularis (V. I.), stigmapterns (Ont. and Que.), ca?iadensis 

 (Ottawa). 



