306 



In a prefatory note to the bulletin Mr. Albert E. Menke, the director 

 of the station, states that the substances experimented with were sug 

 gested by himself, the kerosene extract of pyrethrum having been ob- 

 tained by him in the course of experiments to determine the active 

 principle of pyrethrum. In a letter to us, dated October 28, Mr. Menke 

 announces the discovery of this extract as also the use of veratrin as 

 an insecticide and claims priority for both. Regarding the combination 

 of kerosene and pyrethrum, however, we may call attention to the fact 

 that while it is a matter which we have long had in mind and have 

 suggested to some of our agents, Prof. 0. P. Gillette was the first to 

 give it public mention (p. 184, Bulletin No. 5, Iowa Experiment Station, 

 May, 1889), though his method of preparing it may differ in detail from 

 that of Mr. Men k e. Prof. Jerome McNeill, one of our temporary agents, 

 writes us that the idea of using the combination of these two substan- 

 ces was given to Dr. Menke by him, in conversation soon after the 

 latter's appointment as an agent of this Division, as one of the substan- 

 ces which he Intended to experiment with upon Boll Worms. 



A few interesting notes concerning the natural enemies of the Cotton 

 Worm are published on pages 9 and 10 of the Bulletin. From these it 

 appears that Mr. Davis has noticed a species of Panorpa preying upon 

 the worm, that Trichogramma pretiosa Riley probably destroyed nearly 

 one-fourth of the eggs after the latter part of September, while fully 

 one fourth of the worms subsequent to the second brood were attacked 

 by Euplectruscom stochii Howard. 



The Hessian Fly attacking Grasses in California.— According to Linde- 

 mann the Hessian Ely has been found upon Plileum pratense and Agro- 

 pyruin repens in Eussia, but up to the present year it had not been re- 

 corded as occurring in this country upon any wild grasses. 



We are in position now, however, to add four grasses to the list of its 

 food plants in the United States. In 1887 Mr. Koebele sent us from 

 Alameda, California, specimens of Elymus americanus and of a species of 

 Agrostis which bore puparia supposed to be those of this insect. The 

 adults were not reared, however, and the question remained unsettled. 

 On page 71 of the current volume we published, under the head of 

 " California Notes," a letter from Mr. Koebele in which he mentioned 

 finding Hessian Fly puparia in a grass in the Santa Cruz Mountains. 

 This fact was called in question by Mr. James Fletcher and we wrote 

 Mr. Koebele for s])ecimens and received from him Bromus ciliatus and 

 a species of Agropyrum both carrying puparia. These were very much 

 like the normal puparia of the Hessian Fly, but were smoother and 

 more plump, showing little trace of the longitudinal ridges. Flies were 

 obtained from these and others also obtained from the grasses were 

 sent on by Mr. Koebele, and after comparing these very carefully with 

 specimens from wheat from different parts of the country we find that 



