102 Psyche [October 
NOTES ON THE SPECIES OF THE GENUS DIOCTRIA. 
By CuHarues W. JoHnson, 
Boston Society of Natural History. 
On a window of the Boston Society of Natural History, I ob- 
tained, June 28, 1916, a specimen of Dioctria, but being unable to 
identify it at the time it was set aside to await more material. On 
July 6, 1917, while walking along Rawson Road, Aspinwall Hill, 
Brookline, Mass., I caught four specimens of the same species— 
two males and two females. After a careful study and comparison 
with specimens in my collection from Lyndhurst, New Forest, 
England (co @ ) determined by E. E. Austin, I can only refer it to 
Dioctria baumhaueri Meigen. Wishing to see if the species was 
still to be found, I visited the place again this year (July 4) and: 
captured five males and four females. 
The sudden appearance and apparently restricted distribution 
of a spec’es after so many years of careful collecting in the vicinity 
of Boston, would indicate a comparatively recent introduction, 
possibly on the root of some plants, many of which have in the past 
been ‘mported. The species can be distinguished by the following 
diagnosis. 
Dioctria baumhaueri Meigen. 
Face black with silvery white tomentum, mystax white, front 
and vertex black, shining, antenne black, third joint about as long 
as the first and second together. Thorax with a sparse yellow 
tomentum having two narrow lines of black, a transverse band of 
white tomentum on the pleura extends to the front coxee, also with 
irregular patches above the middle and posterior cox, all the 
coxze with long white hairs below. Abdomen black, shining. 
Front and midd’e legs yellow, a line on the upper side of the femora, 
tips of the tibie and tarsi black, posterior legs black, a spot on the 
under side of the femora at the base, and the base and tip of tibiz 
yellow. Halteres light yellow, wings hyaline. Length, 9-10 mm. 
In Psycue, vol. 24, p. 117, 1917, Mr. Nathan Banks described 
several new species, some of which were formerly confused with 
Dioctria albius Walker, but readily separated by the male genitalia. 
In going over my collect’on in connection with this paper, I have 
