52 



die Lehre , daß der Sitz der Erblichkeitsvorgänge allein der Kern sei, 

 war verfrüht , und wir wissen vorläufig nichts darüber. Wollen wir 

 aber Vermuthungen äußern, so ist es viel wahrscheinlicher, daß die 

 Erblichkeitsvorgänge sowie die meisten anderen Lebensvorgänge in 

 der Zelle auf intimen Beziehungen zwischen Kern und Plasma (oder 

 präcis: dem dirigierenden Theil des Plasma, dem Centrosoma) be- 

 ruhen, und daß wir keinen Grund haben in genannter Beziehung den 

 einen oder den anderen dieser Theile zu bevorzugen. 

 Kopenhagen, Anfang November 1891. 



3. Notes on Parasites, III. On the American Intermediate Host of 

 Echinorhynchus Gigas. 



By C. W. Stile s , Ph.D., of the Bureau of Animal Industry, United States 

 Department of Agriculture, Washington, D. C. 



eingeg. 13. November 1891. 



In 1868 Schneider stated that Melolontha vulgaris acted as 

 secondary host for this parasite. Later, 1887, Kaiser demonstrated 

 that Cetonia aurata was also able to act as secondary host, and he 

 believes further that C. aurata forms the regular source of infection 

 of this curious and dangerous parasite. 



As neither of these insects are found in the United States, the 

 work of Schneider and Kaiser, both of Germany, fails, of course 

 to explain how the American swine become infected Avith the parasite 

 in question, which occurs in nearly all sections of the country. 



Noticing that the hogs around Washington, D.C., very commonly 

 contain this helminth, I determined to find the American insect in 

 which the larval form of the parasite develops. As experiment ani- 

 mals I selected »white grubs« of the genus LacJmosterna , and, placing 

 a number of them in a flower pot, I gave them tender roots, etc. , to 

 eat, upon which I had sprinkled hundreds of eggs which I took from 

 several female specimens of Echinorliynchus gigas. The infection was 

 made Sept. 5th. On dissecting the insect larvae Oct. 20th, I found 

 them enormously infested with larvae of Echinorhynchus in various 

 stages of development. From one «grub« I took at least 300 parasitic 

 Echinorhynchi. As I examined some of the grubs before the experi- 

 ment, and found them free from the parasite, and, as all the grubs 

 examined later contained the characteristic larvae , there seems to be 

 no doubt that the experiment is positive. 



Since making this infection I have learned from my friend, Mr. 

 L. O. Howard, Assistant Entomologist of the Department, to whom I 

 am indebted for the insects upon which I experimented, as well as for 



