PLATYPUS. 95 
21. Apex of elytra truncate, with a vertical subcircular terminal 
impression. . . owe ew wl ee.) 6Q™uadrilobus, sp. n. 
Apex obliquely declivous and produced woe ee ew wwe RR, 
22. Interstices 1, 3,5, 7, 8,9 terminating in spines around the 
declivity 2. 0. 0. 6 ee ee ee ee ee ee 23. 
The outer interstices not spined . . -. -. . 24, 
23. Spine of the 8rd interstice larger than those of the Ist or Sth . acutidens, sp. n. 
Spines of the Ist, 3rd, 5th interstices equal . . . . . . . dohrm, Chap. 
24. Prothorax without pores . . . . .- . = - » 2 6 QD. 
Prothorax with a pore on each side of the anterior rend of the 
sulcus . . . . Le woe oe ew ee OL, 
25. Apical process of elytra subeylindrical or depressed 2. oe ee 26. 
Apical process a vertical quadrate lobe . . . . . + « + biprorus, sp. n. 
26. Third abdominal segment with two spines . . . . . « . flavicornis, Fab. 
Third segment unarmed . . 1 ee ee ee ee ee RY, 
27. Apical process depressed, evidently transverse . . . . . . 28. 
Apical process cylindric, as long or longer than broad... 29. 
98, lst interstice tuberculate from the middle . . . . . . « vtcinus, sp. n. 
lst interstice not tuberculate before the apical carina . . . angustatus, Chap. 
29. 3rd interstice not conjoined with the process by a ridge . . . alternans, Chap. 
3rd interstice conjoined with the process by aridge . . . . 80. 
30. Prothorax subquadrate, feebly emarginate at the sides . . . Jlongulus, Chap. 
Prothorax oblong, strongly emarginate laterally . . . . . porosus, sp.n. 
31. 1st elytral interstice straight to the apex. . . . . 2. «82. 
lst interstice incurved at the apex . . . . . ow +. » haagi, Chap. 
32. 1st interstice conjoined with the upper ridge of the process ; its 
apex not reaching so far back as the posterior elytral border. compositus, Say. 
lst interstice not conjoined with the upper ridge; its apex 
reaching as far back as the posterior elytral border . . . poriferus, Chap. 
33. Interstices alternate at the apex. . . 2 2. eee ee OF 
Interstices not alternate . . . . . ws . . occipitalis, Chap. 
34. Elytra with a vertical lunate impression at apex, the last abdo- 
minal segment spined . 2. 2. . ee ee . . » armatus, Chap. 
Elytra more or less declivons at apex, the abdomen not ; spined . 35. 
35. Interstices not carinate before the apex . . . . . . + . 386. 
Interstices carinate throughout . . . . . . . . . . « pulchellus, Chap. 
36. Apex of the elytra with projecting spines. . - - + + + 37. 
Apex of the elytra not spmed. . 2 2 - 1 7 7 ee ee 88 
37. Postero-lateral angles of the elytra not produced . . . . . ustulatus, Chap. 
Postero-lateral angles produced into aspine . . . . . . « concinnulus, sp. n. 
38. Apical margin of the elytra not emarginate, the 1st interstice 
more elevated than the others. . . . . . . . » marcidus, sp. n. 
Apical margin with a shallow emargination, the alternate 
interstices equally elevated . . . «© . - © « + « ~ eucisus, Chap. 
