144 



Proceedings of the Club. 



§ 8. Habits and forms of Caloptenus spretus. Mr. 

 Scudder offered some remarks on Mr. Riley's account of Ca- 

 loptenus spretus in his recent Annual Report [see Bibl. Rec, 

 No. 311]. The speaker doubted whether these insects took 

 flight from the heart of the Rocky Mts. to the localities in which 

 they were destructive, passing over the wide expanse of arid 

 plains which intervene, because there has been no record of 

 their occurrence in swarms in these plains, and there is suffi- 

 cient ground for the supposition that they may have devel- 

 oped in the immediate vicinity of the regions which they dev- 

 astate. It is well known that among other insects there are 

 years in which individuals are suddenly very abundant, and in- 

 tervening series of years in which few are to be found. It is 

 also known that a few of these locusts can be found in Kansas 

 and Missouri, and in fact from Texas to Manitoba every year, 

 so it seems hardly necessary to look so far for the derivation of 

 the destructive swarms. Moreover, the circumstance, men- 

 tioned by Mr. Riley, that the locusts get tired after repeated 

 flights, is an additional argument against the supposition that 

 they came from a great distance, for the rate at which their 

 strength diminished seemed out of all proportion to the activity 

 of the insects at the time of their first ravages. 



Mr. Scudder also doubted the specific and perhaps even the 

 varietal rights of 0. Atlanis, described by Mr. Riley from the 

 White Mts., for specimens of 0. spretus have been found in 

 different eastern localities, and, like many other insects of wide 

 latitudinal distribution, have shorter wings than the western 

 forms. Mr. Riley gives no characters of importance to distin- 

 guish C. Atlanis from 0. spretus. 



Some conversation ensued, upon the migrations of locusts in 

 Europe and Asia, and it was remarked that in those countries 

 the locusts come from the east westward, while in our territo- 

 ries the migrations are toward the east. This was explained to 

 be probably on account of the direction of the wind, which in 

 our western territories is for much the greater part of the year 

 from the west. (June 11, 187 5. ~) 



No. 21 was issued Jan. 14, 1876. 



