MUSEUM OF COMPARATIVE ZOOLOGY. 11 



Subfamily ACRIDIN^. 

 Schistocerca melanocera. 



Plate II. Figs. 5, 6. 



Acndium mdanocerum StRl, Eug. Ilesa, Ins Orth., 326-327 ; Walk., Cat. Derm. salt. 



Brit. Mus., III. 582 ; Bull., Proc. Zool. Soc. Lond., 1877, p. 88. 

 Acrkl'nun (Schistocerca) inelanocerum Stal, Rec. Ortli., I. 65. 

 Schistocerca melanocera Brun.!, Proc. U. S. Nat. Mus., XII. 19.3. 



1 Acridium tibiale Walk., Cut. Derm. salt. Brit. Mus., IIL 582-583; IV. 620; V., 



Suppl., 60. 



This species was described by Stal from one or more females from the 

 Galapagos without specification of the Lsland from which they came, — judging 

 from size only, probably from Charles or Indefatigable. Walker makes no 

 specification of the separate islands in the Catalogue of the British Museum, 

 but Butler records apparently the same specimens from Charles and Albemarle 

 Islands. Bruner records it from Indefatigable, Charles, James, Albemarle, and 

 Duncan ; Riley, in an unpublished report, from Charles and Indefatigable. 

 Baur collected it on several of these, and also on Chatham, Jervis, and 

 Barrington ; Professor L. Agassiz, on Charles, Albemarle, and Indefatigable ; 

 and Mr. A. Agassiz, though he collected no specimens of this s^jecies on 

 Chatham Island, leads one to infer (Bull. Mus. Comp. Zool., XXIII. 68) that 

 lie saw it there. It is therefore known from eight different islands, or a larger 

 number than any other species of Orthoptera. The 82 specimens seen by 

 nie come from the following : Charles, 13 males, 13 females; James, 1 male, 



2 females; Duncan, 2 males, 6 females ; Albemarle, 16 males, 7 females ; Inde- 

 fatigable, 7 males, 9 females ; Jervis, 1 male; Barrington, 4 females ; Chatham, 

 1 female ; in all, 40 males, 42 females. 



I have subjected all these specimens to a tolerably rigid scrutiny, but I can- 

 not find sutlicient grounds foi' separating those of the different islands as races, 

 much less as varieties or species. The most that this material — all preserved 

 in alcohol — will permit is that there appears a distinct tendency toward 

 tlie formation of races. There is, for instance, distinctly a difference in size 

 between specimens from the different islands, as the following table will show. 

 It contains the results of the measurement of the length of the tegmina of 

 every individual that permitted it ; some were imperfect when captured. 



Inilefatigable, 6 males (44-48), aver. 46.5 mm. 7 females (51-64), aver. 60 mm. 



Chatliam, 1 " 59 mm. 



Charles, 12 males (41-48), aver. 44..3 mm 13 " (52-62), aver. 57 6 mm. 



Barrinj^non, 3 " (52-57), " 54.7 " 



Albemarle, 16 males (42-47), aver. 44.75 mm. 7 " (48-50), " 519 " 

 Jervis, 1 " 44 mm. 



Duncan, 2 " 42 mm cacli. 5 females (49-58), aver. 53.2 mm. 



James, 1 " 38 mm. 2 " (5.5-57), " 56 



Total, 38 " (.38-48), aver 44.55 mm 38 " (48-04), " 56.2 ' 



