98 GKO. H. HORN, M. D. 



The species of this group nearly e(jual in iinmher those of all the 

 p^;eceding groui^s together, and pi-esent the greatest ditfieultv in their 

 separation. The greater number of the sj)ecies had been described 

 from very limited material, and the chai'acters made use of are now 

 seen with more specimens and species to have very little value. On 

 the other hand it has never been found necessary to use the secondary 

 sexual characters foi' the first time. 



The following table will assist in the separation of the species: 



Furm broadly oval, outline at humeri continuous '2. 



Form oblong, thorax narrower at base than the base of elytra 12. 



2. — Entirely testaeeous above palleil!<i. 



Elytra in great part yellow, with merely an elongate-triangular sutui-al area 



blaek <>iiictil!i. 



Elytra l)lack, with discal defined s])ot .3 



Elytra pale at apex, either merely bordered with yellow, or with an ajncal 



area of that color ••••... .4 



Elytra entirely blaek 7. 



3. — Elytra! spot antemedian, nearly oval, anterior angles of thorax yellow. 



pacificiiN. 



Elytral spot veiy o))li([ue, tliorax black iJitritbiiN. 



Elytral sjjot post^median, thorax yeUow at sides flebilis. 



4. — Elytral i)ale apex wide, or even large 5. 



Elytra narrowly pale at apex (>. 



5. — Thorax with median black spot. 



Apical spot not larger than a lifth the lengtii of the suture- • f raterniiM. 



Apical spot fully a third of su])erticial area Briillei . 



Thorax entirely yellow. 



Apical area large wemi ruber. 



(i. — Tliorax jwrtly black. 



First ventral of male with a median smooth area surrounded by short 



pubescence I>iiiiotieoIIij<i. 



First ventral of male without i)ubescence COllarJ!<«. 



Thorax entirely yellow eervicalis. 



7. — Species larger .08 — .10 inch 8. 



Species small .06 inch 11 . 



8. — Metacoxal arc much shorter than first segment abbreviatilS, 



Metacoxal arc nearly as long as the segment 9 



9. — First ventral of male with a tu1)ercle at middle kC |Misterior edge, finely 



pubescent inargiiiicoIIi!>i. 



First ventral male not tuberculate 10 



10. — La.st segnient of male feebly impresso-emarginate. 



Sides of thorax more or less yellow ardelio. 



Thorax entirely black toiiebroriiiN. 



Last segment of males deei)ly impresso-emarginate laciii^tris 



11. — Metacoxal arc scarcely as long as half the segment piiiictiiiii. 



Metacoxal arc nearly as long as the segment. 



Thorax distinctly punctate ; pubescence recumbt^nt nan lis. 



Thorax smooth ; pub(;scenc(! erect utilis. 



