580 XEW JERSEY AGRICULTURAL COLLEGE 



roqucst a. nuinbor of these correspondents collet-ted larviv, and in 

 the laboratory some 200 were gathered together by ]\Iessrs. Brehme 

 and Cirosslxx'k. Mr. Henry Bird, of live. X. Y., who has made 

 ralher a specialty of tlu' moths belonging t(» tliis uroup. was good 

 enough to place at my disposal his notes antl ttbscrvations, and Mr. 

 William Beutennuiller. of tlu' American ^Inseum of Natural History, 

 bred out and observed a lot of the specimens, and was the lirst to 

 actually note the egg-laying period. From tlie information thus 

 gathered, supplemented by personal observatit)n and lal)oratory ex- 

 periments, the following life history is made out. 



Life History. 



'^Fhe moths make {heir appearance in early So])tendier and lay their 

 eggs, preferably on the stalks of ragweed, but also on dock, pigweed 

 or almost any other thick-stalked weed that they can find. It is 

 ])robable that, in the absence of oth<M' jtlants. eorn. tomato oi- potato 

 stalks would be used. The eggs are eompared by Mr. Beut<Mmiuller 

 to a minaturc niuskmelon, llattened above and bi'low, with the sides 

 grooved. An individual female may deposit 400 or more of them, 

 this number being determined by counting the eggs in the body of some 

 of the females that were bred in the ofhce. 



The eggs remain on the jdants during the winter, and hy far the 

 greater number perish before the advent of spring, ^uch as do sur- 

 vive hatch during the last days of May and early davs of dune, and 

 the little caterpillar bores into the stem of the first suitable plant that 

 it can find — ragwin-d preferred. A great many of these small plants 

 die as the result of the attack, and the larva is compelled to change 

 its quarters. It is even likely that other reasons may induce a change, 

 and toward thi' <'nd of dune they a])pear in the cultivilted ])lants. 

 Growth is hot rapid, and it requires the whole time between the be- 

 ginning of dune and the end of August — a period of nearly or quite 

 thrci' months — to mature the caterpillar. The most ra]>id feeding 

 seems to occur in late June and early didy, when the elTeet upon the 

 })lants becomes most noticeable. 



* In August, sometimes a patch of the giant ragweed will havi' every 

 stalk infested, and burdock is only less susceptilde to attack. Infested 

 plants are readily recognized by an irregular, bhukened hole in the 

 st«'m, near the base, through which the excrement is forced. From the 



