62 ENTOMOLOGICAL SOCIETY OF ONTARIO. 



THE EOCKY MOUNTAIN LOCUST AND ITS ALLIES IN CANADA. 



By Samuel H. Scudder. 



The genus Melanoplus, to which the Rocky Mountain Locust belongs, forms 

 part of a small group of genera first definitely separated a few years ago by Brunner yon 

 Wattenwyl under the name of Pezotettiges, but which, for reasons given in a technical 

 memoir now in press, I have preferred to call after the dominant genus just men- 

 tioned, — Melanopli. 



In the last resort, the Melanopli are separated from their nearest allies only by such 

 an apparently insignificant matter as the number of spines (in itself variable) found on 

 the outer margin of the hind tibiai ; these, save for individual exceptions, often on one 

 side of the body only, are always at least nine in number and rarely exceed fourteen. In 

 the known Canadian species they range from eight to thirteen, but ten or eleven is the 

 almost invariable number. 



The Melanopli are an almost exclusively American group comprising more than thirty 

 genera of which oiily one, Podisma, occurs in the old world. They are primarily divided 

 into two sections, dependent on the shape of the subgenital plate of the males, a division 



Locust (magnified.) 



which broadly but not exactly separates the tropical or subtropical genera from those of the 

 temperate regions, and leaves an almost equal number of genera in each section. Of the 

 tropical section, as it may be called, but a single genus is known in Canada, Hypochlora ; 

 its single species H. alba (Dodge) is reported by Brunner as occurring in Manitoba, and 

 this is altogether probable as it ranges along the border in the United States from Minne- 

 sota to Montana, but extends south only to Kansas and Colorado. It is a slender, hoary 

 green, lon»-le»ged insect with abbreviated tegmina, and is partial to the white sage, Arlem- 

 isia ludoviciana. 



Of the temperate section, only three of the genera are actually known to inhabit 

 Canada, though, as we shall see, there is little doubt that others will be found there. 

 One of these is Podisma, formerly known as Pezotettix*, a genus remarkable among the 

 Melanopli for its longitudinal range, which is around the globe north of Lat. 35° N. ; for 

 its penchant for high altitudes, many of the species occurring only above or at the forest 

 line on high mountains ; and for the wide separation of its sternal lobes, though this alone 

 will not separate it from all Melanopli. Moreover its organs of flight are never com- 

 pletely developed and may often be altogether wanting, as may then also, though in none 

 of our American species, the tympanum found on the sides of the first abdominal segment ; 

 as this tympanum is regarded as an auditory apparatus, and as the power of producing 

 sound is gone with the loss of the tegmina (against which the femora are scraped,) the 

 absence of the tympanum in some apterous European species would seem to indicate that 

 they had departed the more widely from the original type, and had therefore a longer 

 history behind them. 



*See Psyche, vii, 395. 



