TRIBOLIUM. 329 



joints, and gradually dilated toward apex. L. If — 2 1. 

 Scarce. T. confusum, Duv. 



G^iatliocerus. 



Somewhat elongate, parallel-sided, only slightly convex. 

 Red-brown. Thorax broader than long, sides straight 

 behind ; elytra with rows of punctures, fourth and fifth 

 shorter. Mandibles of male very large and prominent. 

 L. 1| — 2 1. Common. G. corniitus, Fab. 



Hypojthloeus, 



A. Eefiexed margin of elytra prolonged to sutural angle ; 

 elytra covering or nearly covering pygidium. 



Rust-red, slightly shiny. Thorax as long as broad ; 

 elytra not much more than twice as long as together broad, 

 punctured in rows throughout. L. 1^ — Ih 1. Not common. 



H. depressus, Fab. 

 S, Reflexed margin of elytra not prolonged to sutural 



angle ; elytra not covering pygidium. 



a. Elytra with rows of punctures (except at apex), uni- 

 colorous. 



Dark reddish-brown, shiny ; antennae and legs lighter. 

 Thorax longer than broad ; elytra nearly three times as 

 long as together broad. L. 2| — 3 1. Not uncommon. 



H. castaneus, Fab. 



b. Elytra confusedly punctured, bicolorous. 



Rust-red ; elytra black from before middle to apex. 

 Thorax slightly loDger than broad. L. IJ — If 1. Com- 

 mon. H. bicolor, 01. 



Alphitobius, 



A, Basal border of thorax interrupted in middle. 



Upper-side pitch-black, shiny ; under-side brown or rust- 

 red ; antennae and legs brownish. Thorax broadest near 

 base, punctuation stronger at sides than on disc. L. 2| — 

 2f 1. Rather common. A. diaioerinus, Panz. 



jB. Basal border of thorax not interrupted in middle. 



Upper-side pitch-black, slightly shiny; under-side brown; 

 apex of antennae and legs red-brown. Thorax broadest 



