SCHISTOCERCA, SPHINGONOTUS AND HALMENUS 43 1 



than on those of Tower ; and, in all, the post-ocular stripe is present 

 on the head, being not absent on the head in the Tower specimens as 

 tabulated by Scudder for his specimens. On the Hood Island speci- 

 mens the lateral prozonal markings average much less distinct than on 

 those from Tower or Chatham. With regard to this character, then, 

 the Tower specimens are intermediate between the other two but closer 

 to the Chatham form. The maculation of the tegmina is certainly 

 darkest and the spots are largest, especially basally, on the Chatham 

 specimens, while in this respect the Hood and the Tower specimens are 

 almost identical and do not show the differences described by Scudder 

 from his specimens. The differences in the color of the veins and 

 reticulation of the post-median area of the fore-wings, pointed out by 

 Scudder, namely that the Tower form has these parts pale gray and the 

 others brown, is true of all the specimens, and gives the Tower race a 

 paler appearance. 



These comparisons show that no one of the three varieties is more 

 closely related to one than to the other of the other two. S. I. hyalina 

 of Tower is the only one that possesses a character not shared in some 

 degree by the other two — the pallid color of the veins and reticulations 

 of the fore-wings distinguishes it from the others — and hence it is 

 probable that the Tower race has been derived from the inhabitants 

 of one of the other islands, rather than that the others were produced 

 separately from a form with pale wing veins. However, since either 

 of the brown-veined forms may have been derived from the other after 

 it had come from a pale-veined form, there is no certain evidence at all 

 that any one rather than either of the othei's might be the ancestral race. 



SCHISTOCERCA INTERMEDIA sp. nov. 



(PI. xxvii, fig. 3.) 

 From Duncan Island. 



Descriptio7t of the Type. Fe77iale. — General color of the head 

 yellow, a brownish area at lower end of frontal costa, clypeus and 

 labrum with dusky markings, frontal lunule dark on sides, a post- 

 ocular stripe present narrowly split with yellow, a short black stripe 

 extending from lower border of eye half way down middle of gena, 

 a distinct yellowish vertical stripe reaching to frontal costa, space 

 between this vertical stripe and the eyes and post-ocular stripe punc- 

 tate with black, a few black punctations on anterior edge of gena 

 below front of eyes. The general color of the head is thus marked 

 off by the black into several areas; one of these is along the posterior 

 part of the gena from the post-ocular stripe and eye down to the lower 

 border of the gena ; another is below the anterior part of the eye in 



