THE CANADIAN ENTOMOLOGIST 279 



Syrhula admirabiiis Uhler is also a very common Acridian at 

 Thompson's Mills, especially in the dry fields grown up to broom 

 grass. The male is rather musical, producing a weak, lisping 

 stridulation at intervals — s-s-s-s — s-s-s-s-s-s-s, by sawing the hind 

 femur upon the edges of the tegmina. 



Arphia xanthoptera Burm. A common locust in old fields at 

 Thompson's Mills. The notes are a loud, harsh crackling, accom- 

 panying their flights across the fields. 



Arphia sulphur ea Fabr. In fields, pastures, etc. A noisy 

 crepitation during flight is the only method of stridulation. 



Spharagemon bolli Scudder. Very common in old fields at 

 Thompson's Mills and in pastures. It has been observed that 

 this grasshopper sometimes hovers in air and produces a rustling 

 note similar to the habit of Dissosteira Carolina, but I have not 

 witnessed this myself. The usual note is a rattling noise during flight. 



The Acridiidae confine their habitat almost entirely to the 

 ground stratum, whether in wood or in field. Few species regularly 

 prefer the true herbage or shrub stratum of vegetation, as do many 

 members of the Locustidaj and Gryllidae. Even those species 

 which appear to prefer wooded situations confine themselves to 

 the more open, sparsely grassy areas as Melanoplus scudder I and 

 some of the Tettigina. I have found no species inhabiting deep 

 woods where the ground is hidden with dense herbage. Orthoptera 

 of all kinds are uncommon in such situations. 



Tryxalis brevicornis perhaps belongs more strictly to the true 

 herbage stratum of vegetation than any other species listed in 

 this paper. 



The species of Schistocerca, i. e., americana, alutacea and 

 damnifica, do not confine themselves strictly to the ground stratum, 

 nor can they be considered truly members of the herb and shrub 

 strata. They are somewhat elastic in their habits, however, and 

 show a more marked tendency to choose the habitat of the higher 

 leaf and shrub strata occasionally, than do most Acridiidae. 



This does not by any means complete the list of Acridians 

 probably occurring at Thompson's Mills, but many years of 

 patient study and collecting must be pursued to determine the 

 Orthoptera inhabitating any region, and to become familiar with 

 their habits and stridulations. 



