75 



Of southern species both the cotton worm and the boll worm moths 

 are to be found very late in the season, and the writer has seen the cot- 

 ton-worm moths in November in great numbers at Ithaca, N. Y., at 

 light, after most other insects had been absent from lights, at least 

 in any numbers, for weeks. Immense numbers of the moths were 

 attracted to the electric lights on the principal streets of the city. 1 



Larvae of two important species, the imported cabbage butterfly, 

 Pieris rapce and the diamond-back moth, Plutella cruciferarwn, both 

 of comparatively recent introduction, were found during the winter of 

 1899-1900 in the last week of November freely feeding after several 

 frosts. They were accompanied by the harlequin cabbage bug, Mur- 

 gantia histrionica, which we know to have recently spread northward 

 from the Southern States, and by the cabbage looper, Plusia hrassicce, 

 which has also spread from the south northward, though not in very 

 recent times. 



SUMMARY OF CONCLUSIONS. 



The result of recent studies may be summarized briefly as follows: 



(1) That there is a tendency on the part of forms introduced in the 

 North from farther South to produce one or more generations in excess 

 of the number developed by similar forms native to the region of this 

 adopted habitat. 



(2) That as a result these forms remain later in the field than do 

 species native to the North. 



(3) That, largely as a result of the above and other habits, in addi- 

 tion to greater susceptibility to low temperatures, these southern intro- 

 ductions are apt to be destroyed every year in large numbers, their 

 residence in their northern homes being, therefore, not strictly per- 

 manent. Cold snaps following warm spells during the winter are, ac- 

 cording to observation, the most important factors in their destruction. 



ON THE HABITS OF ENTILIA SINTJATA. 



By L. O. Howard. 



This interesting little leaf-hopper, certain of the habits of which 

 have been described by Mrs. M. E. Rice, of Coryville, Pa., in Volume 

 V of Insect Life (pp. 243-245), is common throughout the eastern 

 United States, and may be found upon many different plants, such as 

 potato, ragweed (Ambrosia), spikenard (Aralia), Cnicus altissimus, 

 Lactuca spicata, Rudbeckia laciniata, cotton, sunflower, and other 

 annual and herbaceous forms. Mrs. Rice studied the eggs, which 

 were laid upon the midrib of a leaf of sunflower and began to hatch 



1 The exact date was not noted, but it is much colder in that locality than on the 

 corresponding date in Washington, there being about a month's difference in that 

 climate in ordinary seasons, and although the event happened many years ago, it is 

 remembered that a heavy overcoat worn at the time was very comfortable. 



