108 



by repeated stings ana jerks it would linally be dislodged, when the 

 wasi) would again sting it and then fly away with it to its cell as food 

 for its young. 



A few days before I had found on an old golden-rod stalk in an open 

 woods four cells of the Potter Wasp, and all were filled with larvse, 

 many of which were the larva} of the Parsnip Web-worm, and all of 

 them nearly the same size, the size, no doubt, easiest to dislodge, or at 

 least easiest to carry. 



Last summer, 1S91, I discovered another means at work reducing 

 the larviTB of the AVeb-worm. Along a great ditch that ran through the 

 farm the parsnips were very abundant, and on them I found that some 

 disease, apparently, had destroyed many of the larvfe, they being dead 

 in their webs and of a black color and in every case very soft and 

 flabby. This I attributed to a fungus attack, for in this strip about 

 five eighths of the larvfe were dead. I collected a large number of them, 

 but could find no marks ot the sting of a wasp upon them, for I thought 

 perhaps this might have something to do with their destruction. While 

 the tendency of the poison of the wasp is to preserve them alive, 

 although paralyzed for a while, 1 therefore tried to find some that were 

 in this condition, perhaps recently stung, but could find none but what 

 were black and flabby; and this, with the fact that I could find none of 

 the dead ones on any other part of the farm, led me to believe that the 

 destruction was due to some bacterial ( ?) germ, perhaps. 



Dr. Riley quotes Stainton as saying that the eggs of the Web- worm 

 are deposited in the spring by the hibernated female moth upon the 

 undeveloped umbels of the Parsnip, and Dr. Riley adds that it is not at 

 present known whether there are two broods, though this is quite prob- 

 able. 



It seems to me it would be poor economy to force, at such an early 

 date, these moths into hibernation, for the dangers from their natural 

 enemies would be so great at that season, as to almost, if not quite, ex- 

 terminate them. With this end in view I have diligently searched for a 

 second brood, and thought they would be found on the Wild Carrot later 

 in the season, but all my searching has foiled to reveal a single larva 

 of this moth on the Wild Carrot, although this plant was everywhere 

 abundant, to a degree detrimental to the growth of grass and other 

 crops. 



I placed a lot of the moths in a roomy cage with j)lants of the Wild 

 Carrot, but they seemed to care for nothing, but were continually 

 crawling under anything that would cover them, or they would remain 

 quiescent at all times. No eggs, as far as I c-ould discover, were ever depos- 

 ited, although they lived for some time, and the carrots with roots also 

 gave them ample temptation, as they were growing, to do so. I dark- 

 ened the cage, but that did not seem to make them any more active. 

 When disturbed they would dart about with great rapidity and force. 

 I kept some of them until the 29th day of August, and, although the 



