CEDEMERID^E OF BOREAL AMERICA. 395 



The male has the last ventral segment deeply triangu- 

 larly incised and the sexual apparatus has the spoon- 

 shaped claspers usual in the genus. 



One specimen. Marin County, California. 

 Xanthochroa centralis n. sp. 



Form slender and elongate, piceous; thorax reddish 

 yellow, with a small piceous spot at middle. Antenna? 

 black. Head piceous, front yellow, very sparsely punc- 

 tate. Thorax as wide as long, sides arcuate in front, 

 then oblique, at base slightly expanded, disc smooth, very 

 sparsely punctate, a slight concavity which is piceous. 

 Elytra densely punctate, subopaque, distinctly subcostu- 

 late, sparsely pubescent. Body beneath piceous, shining, 

 sparsely punctate. Legs entirely piceous. Length .28-. 36 

 inch. ; 7-9 mm. 



In the male the fifth ventral is in great part pale, 

 deeply and densely triangularly emarginate. In the 

 female the segment is also in great part yellow, obliquely 

 prolonged and acute at tip, elevated along the middle and 

 deeply concave each side. 



In a large number of specimens seen very little varia- 

 tion has been noticed. Rarely the central piceous spot 

 of the thorax is absent, and almost as rarely specimens 

 occur with a small additional black spot each side. 



Sylvania, California. (Ricksecker.) 



Alloxacis n. £. 



Form slender. Head oval, not prolonged. Eyes very 

 feebly or not at all emarginate. Antenna? slender, eleven- 

 jointed in both sexes, in contact with the eyes at base 

 (except in dorsalis). Last joint of maxillary palpi trian- 

 gular, widest at middle. Mandibles dissimilar, that of the 

 left side simple and acute at tip, that of the right side 

 bifid, with the upper tooth shorter. Tibia? with two 



