OF WASHINGTON, VOLUME XIV, 1912. 219 



A NEW INJURIOUS PLUTELLA. 



BY AUGUST BUSCK. 

 Plutella armoraciae, new species. 



Labial palpi ochreous white with a longitudinal, dark golden-yellow 

 streak on the tuft of the second joint exteriorly. Face and crown of head 

 chalky white; sides of the head yellow. Thorax white; patagina yellow. 

 Fore wings light saffron yellow with costal edge narrowly white and with 

 a series of single deep black scales along the dorsal and terminal margin to 

 apex. Cilia whitish yellow. Hind wings silvery white with light fuscous 

 edges and light yellow cilia. Abdomen ochreous white above; entire body 

 white below. Legs white, with the numerous short spines on the underside 

 of the tarsal joints deep black, contrasting conspicuously with the light 

 color of the legs. 



Alar expanse, 16 to 18 mm. 



Food plant: Horse-radish (bred by Mr. H. O. March). 



Habitat: Rocky Ford, Colorado. 



Type: No. 15388, U. S. National Museum. 



Intermediate between P. omissa Walsingham and P. 

 porrectella Linnaeus, but amply distinct from either; differing 

 in the yellow color and the marginal spots from the former; 

 and differing in the lack of wing ornamentation otherwise 

 from P. porrectella. 



The injury caused by this species to horse-radish in Colo- 

 rado is of some economic importance and the present descrip- 

 tion is published at this time in order to provide a name for 

 it in a forthcoming publication of the Bureau of Entomology, 

 U. S. Department of Agriculture. 



BLOOD-SUCKING INSECTS AS TRANSMITTERS OF HUMAN 



DISEASE. 



BY FREDERICK KNAB. 



In the September number of our Proceedings (pp. 180-181) 

 Dr. C. T. Brues discusses remarks by the writer, made at 

 the meeting of January 4, 1912, and published in our June 

 issue (pp. 79-81), on the association with man of those blood- 

 sucking insects that have proved to be disease-transmitters. 

 It was not my intention to review the entire field of insect 

 transmission of disease, but simply to point out that in the 

 case of insect-borne blood-diseases such association does exist. 

 I aimed to make it clear that my remarks were restricted to 

 diseases caused by parasites requiring alternate hosts. Being 

 aware of the contradictory or seemingly contradictory facts, 

 and appreciating that my remarks were open to some of the 



