196 DESCRIPTIONS OF NEW SPECIES. 



516. S. senex. Niger opacus, pube brevi minus subtili cinerea 

 vestitus, piothorace fortius, elytris subtilius puuctatis, his margine 

 suturali laterali apicali et scutello fulvo-pubescentibus. Long. 13 — 

 17 mm. 



Arizona, collected by Drs. Horn and Palmer ; the rapidity of 

 flight of this, insect is wonderful. The pubescence of the elytra 

 is less dense than that of the under surface, and not evenly dis- 

 tributed, so as to give a mottled appearance. The outer con- 

 dyle of the thighs is elongated into a short obtuse process. 



CROSSIDIUS Lec. 



The species of this genus vary greatly in color, and are some- 

 what difficult to recognize by the scattered descriptions here- 

 tofore published. I have constructed the following table to 

 enable them to be more easily identified : — 



A. Prothorax subquadrate ; 



Black clothed with long gray hair ; elytra very densely punctured, punc- 

 tures very coarse at the base, becomiug finer behind ; front tibiae with 

 a deuse brush of hair on the inner side. Utah ; Eastern California. 



1. ater Lec. 



B. Prothorax rounded and subtuberculate on the sides ; 



a. Elytra very coarsely punctured towards the base, punctures be- 



coming smaller behind ; 

 Head, antennae, and legs black; under surface and pronotum black or 

 rufous; elytra rufo-testaceous with basal margins and sutural blotch 

 black, the latter usually narrow or wanting in £ , broad in 9 . 



2. punctatus n. sp. 

 Testaceous, antennae fuscous, legs ferruginous ; elytra with two costae 

 more distinct than in the other species. Colorado Desert. 



3. testaceus Lec. 

 Testaceous, antennae fuscous, legs ferruginous ; elytra without costae, 



suture black, broader in £. Arizona. 4. intermedius Ulke. 



Smaller ; antennae, legs, and head black ; under surface yellow, trunk 

 frequently, abdomen rarely blackish ; pronotum more or less black ; 

 elytra yellow with humeral spot and sutural blotch more or less di- 

 lated, black. Colorado and New Mexico. 5. pulchellus Lec. 



b. Elytra less coarsely punctured, punctures smaller towards the 



tip; 

 Black, abdomen usually ferruginous; elytra rufo-testaceous, with basal 

 margin, and usually the whole of the suture black, the blotch never 

 very much dilated ; front tibiae with a dense brush of hair on the inner 

 side. Oregon. 6. hirtipes Lec. 



C. Prothoiax rounded on the sides, not angulated ; 



