60 



and it seems probable that we will have no such numbers the coming 

 season. 



Both of the above species are quite subject to bacterial and other 

 diseases, and diseased individuals of both were noticed, but the extent 

 of infection was not estimated. 



No complaints of injury by either species in any portion of the 

 country have come to my knowledge, although a few specimens were 

 sent in by correspondents in the South. In this connection comparison 

 is made with the observations of Messrs. Johnson and Quaintance. 

 The former reported the cabbage looper as having ruined hundreds of 

 acres of cabbage in Maryland in 1898, but hardly a specimen was 

 obtained in the trucking areas the present year. In Georgia, according 

 to Mr. Quaintance, only a single larva was observed. The experience 

 of the latter gentleman as to the comparative abundance of the two 

 tobacco worms agrees with my own. 



It would seem probable also that the pickle worm owes its destruc- 

 tion to other causes than temperature, since the same rarity has been 

 noticed in Georgia as about the District of Columbia. A bacterial 

 disease is suspected, as the related nitidalis has been observed by the 

 writer to die from this cause. 



From the examples given it is reasonably plain that weather which is 

 unfavorable to insects properly belonging to the Lower Austral life 

 zone and which extend their range into the warmer portions of the 

 Upper Austral, as in and near the District of Columbia, may favor 

 the development of Transition forms, and vice versa. With our knowl 

 edge of the effect of the latest cold spell we ought to be able to predict 

 with tolerable certainty, provided other forces with which we are unac- 

 quainted are not also at work, a similar result following the same 

 or similar conditions in future years. 



As regards the immediate future, there is every probability that the 

 conditions in the region under consideration, as well perhaps as in 

 other regions having the same fauna, will not be materially changed 

 next year from what they have been the past season; and if ihe pre- 

 diction of some wiseacre whom the writer has seen quoted that the 

 winter 1899-1900 will be a severe one is verified, there is strong proba 

 bility of a continuance of present conditions, leading perhaps to an 

 even greater lecrease in southern forms and to a corresponding increase 

 in northern species. 1 



PROBABLE DECREASE IN INJURY TO CUCURBIT AND CRUCIFEROUS 



* CROPS. 



It will be noticed by anyone who is conversant with the habits of 

 the insects enumerated as being affected by atmospheric changes, para- 

 sites, and diseases, that it includes a considerable number of those 

 which attack squash, cucumber and other cucurbit crops; cabbage, 

 turnip and other cruciferous plants, and rosaceous and other small fruits. 



'The writer does not desire to be understood as in any way forecasting the future, 

 but merely as expressing the belief that certain results would naturally follow 

 certain conditions. 



