8 



tion of the weeds. It is to be regretted that no harmless inexpen- 

 sive, but effectual remedy has ever been discovered for the destruction 

 of these pests. 



I do not think that the Purple Cabbage-worm {Pionea rimosalis, 

 Guenee) has ever made its appearance in this locality; at least I 

 have never met with it, although for the past two or three seasons 

 I have paid especial attention to collecting and rearing Lepidopter- 

 ous larvae. The present season a closely allied species — the Pionea 

 stramentalis of Hubner — appeared in considerable numbers upon the 

 Horseradish, and as almost every insect which feeds upon the 

 horseradish will also feed upon the cabbage, I have no doubt that 

 this insect will some day prove to be destructive to this last named 

 vegetable which already has a host of insect foes. 



The Army Worm {Leucania unipuncta, Haworth) appeared in a 

 few localities in destructive numbers and seemed to be more de- 

 structive to oats and timothy than to any other grain or grass. I 

 am happy to be able to present in the following pages a history of 

 this insect which is carried far enough to forever set at rest the 

 question of the number of annual broods, and the state in which 

 the insect hibernates, at least so far as they apply to this locality, 

 and also to the sedentary race of Army "Worms, for it is my firm 

 belief that there are two distinct races of these insects, and that 

 the one race has no connection whatever with the other. As I have 

 given in the chapter upon this insect the reasons upon which this 

 belief is founded, it will be unnecessary for me to repeat them in 

 this place. My brother, Mr. A. G. Coquillett, has aided me much 

 in studying up the life history of this insect ; he brought me the 

 only specimens of the hibernating brood that I have ever seen. I 

 had found many specimens of the earlier broods under boards, 

 sticks, etc., but was unable to find a single specimen of the last, 

 or hibernating, brood in these situations, although I spent much of 

 my time searching for them. 



A kind of naked caterpillar somewhat resembling the Army Worm 

 appeared in considerable numbers in the months of August and 

 September, and was quite destructive to the green heads of timothy. 

 They were found at their work on cloudy days and appeared to con- 

 fine their attacks entirely to the heads, as I never saw any feed 

 upon the leaves. In quite large fields of timothy which I examined 

 fully nine-tenths of the heads had been more or less injured by 

 these worms. The latter quite closely resemble the Wheat Head 

 Army- worm (Leucania harvcyi, Grote) but are much paler ; they may 

 be but a pale race of this species, however, as the sedentary race 

 of Army-worms are considerably paler than those belonging to the 

 migrating race. Quite a number of these timothy worms assumed 

 the chrysalis form, in the month of September, but as they have not 

 yet been changed to moths I am unable to determine the species. 



On the 21st of November I received from the Editor of the Ger- 

 mantown Telegraph a box of insects for determination. The enclosed 

 insects proved to be the larvae of the Silver-marked Moth (Plusia 

 simplex, Guenee), and in the letter which accompanied the box, the 

 Editor stated that these larvae were very destructive to the Celery 

 in many gardens in his locality. This is the first instance that has 

 come to my notice of these larvae feeding upon this plant. In my 



