BY T. Q. SLOANE. 579 



texana) ; but, in most of the present-day species, this has 

 deepened into piceous, or black. Macrocheilus has yellowish 

 spots on the elytra, Helluomdius eyanipenne has the elytra 

 bright greenish-blue, Dicranor/lossus resplendens, and jEnig- 

 ma iris have the whole upper surface cyaneous. One concludes 

 that species of a polished, black colour are derived from duller 

 coloured ancestors, and that those with bright colours are still 

 more advanced in the matter of colour.^ 



Important Characters. — Antennce: the longer and more 

 slender the antennae are, the more they depart from the ances- 

 tral type ; as the fourth joint becomes more cylindrical and 

 less pubescent, so does it become more specialised. Palpi : 

 the penultimate joint of both the labial and maxillary palps 

 varies greatly in length, being shortest in Helluodema uni- 

 color, and longest in (xit/adema hostocki and allied species. 

 Ligula : the form is very variable in different genera, as given 

 in the generic diagnoses which follow. [It may be noted that 

 I follow Dr. G. H. Horn in applying the term labium to the 

 whole organ (i.e., ligula and paraglossae), and in restricting 

 the term ligula to the central piece alone.] Paraglossce,-. the 

 form of the labium in the Helluonini, in respect to its para- 

 glossae, has been the subject of controversy. Bonelli, when 

 diagnosing the genus TIelluo, described the labium as without 

 paraglossoi; this view was adopted by Lacordaire in his 

 "Genera des Coleopters," though he was aware that Schmidt- 

 Goebel, in 1847 (Coleop. Birman.), had described the para- 

 glossae of Macrocheilus as united with the ligula, and appear- 

 ing as if wholly ivanting ; Dr. G. H. Horn adopted Schmidt- 

 Goebel's opinion in his "Genera of Carabidae"(1881), and de- 

 clared the usual idea that the labium was without paraglossse 

 to be "quite erroneous." The view of Schmidt-Goebel is 

 strictly correct, but Bonelli's idea is not "quite erroneous." 



* In this connection, I note from my collection : one specimen of 

 Gigadema hostocki var. intermedia, from Jerilderie, N. S. W., shows a 

 distinct, dull reddish spot near the apex of one elytron; and two speci- 

 mens of G. noe.te, from Cooktown, two similar spots, one on each elytron. 



