OF WASHINGTON. 181 
had been found about Washington, and larvae and imagos of the 
latter had been found by Mr. Koebele in California on beaver 
skins received from Alaska. The relations of these larvae to 
those of Platypsyllus were pointed out. 
Prof. Riley also made a communication on the manner of 
ovi position in Thalessa. Thalessa is proved to be an external 
parasite of Tremex. In laying its eggs it usually inserts its 
ovipositor into a hole made by some insect which has emerged 
from the infested tree, but it is able to penetrate solid wood. The 
jaws of the larva of Thalessa are not adapted to boring in wood. 
J. A. Lintner and J. S. Woodward have stated that Thalessa also 
deposits its eggs in larvae of Dataita, but Prof. Riley believes 
this to be an erroneous statement, and as Heteropelma resembles 
Thalessa, and has been reared from Datana integerrima and 
D. ministra, it is probable that these authors have mistaken 
Heteropelma for Thalessa.* 
Mr. Schwarz exhibited a Telamona having a globular sac pro- 
jecting equally above and below the surface of its carapace. He 
supposes this sac to be formed by a parasite, in a manner similar 
to that in which Gonatopus, a Proctotrupid, forms a sac on cer- 
tain Rhynchota. 
JANUARY 3, 1889. 
Fourteen persons present. President Schwarz in the chair. 
Mr. C. L. Marlatt was elected a member of the Society. 
The election of officers for 1889 then took place and resulted 
as follows : 
President, E. A. Schwarz; ist Vice-President, Dr. C. V. 
Riley ; 2d Vice-President, Dr. George Marx ; Recording Secre- 
tary, Div Wm. H. Fox ; Corresponding Secretary, Tyler Town- 
send ; Treasurer, B. P. Mann ; Members of Executive Com- 
mittee, L. O. Howard, Theo. Pergande, C. L. Marlatt. 
The retiring President then delivered his Annual Address : 
*See Insect Life, vol. i, pp. 168-179 (Dec., 1888). 
