146 THE PLUM CURCULIO. 
In reality, however, the percentage of parasitism, as shown in 
these several tables, is too low, since it is based on the total number 
of larve which were placed in pots of soil or other container. In all 
rearing work a considerable proportion of larve, aside from those 
killed by parasites, failed to develop to adults, from various causes, 
as immaturity, etc. Taking the total emergence of beetles and para- 
sites as a basis, the percentage of parasitism for the season of 1908 
at Washington, D. C., was 8.32; at Siloam Springs, Ark., 5.44; and 
at Barnesville, Ga., in 1910 it was 11.96. Even these figures are 
probably too low, since the removal of the infested fruit from the 
orchard to the laboratory must have prevented a certain degree of 
parasitism that would normally have occurred in fruit lying exposep 
in the orchard. 
(Sigalphus) Triaspis curculionis var. rufus Riley. 
This variety was described in his Third Missouri Report, page 27, 
by Riley, who states that it is slightly larger and differs so remark- 
ably from the normal form that were it not for the absolute corre- 
spondence of all of the sculpturing of the thorax and body, and the 
venation of the wings, it might be considered distinct. The great 
length of the ovipositor is very characteristic. Concerning this 
variety in Iowa Prof. Gillette observes (Canadian Entomologist, 
vol. 22, p. 114): 
The variety rufus appeared much more abundant than curculionis in my breeding 
cages last summer. The two forms differ so much from one another, and in some 
respects, especially in the number of joints of the antennz, from Riley’s description 
that I have made the following notes upon them: “* * * Rufus is decidedly more 
robust in every case than curculionis, and were it not for the fact that so eminent an 
authority as Dr. Riley considers them the same species, I should think that rufus 
ought to be raised to the rank of a species.”’ 
Attempts were made by Prof. Riley to distribute both the Sigal- 
phus and Porizon parasites, specimens being sent to several corre- 
spondents from Kirkwood, Mo. In the bureau collection of Sigal- 
phus reared from the curculio, 725 specimens, only 40 are of the 
rufus variety, from the following localities: Fort Valley, Myrtle, and 
Barnesville, Ga.; Valparaiso, Ind.; Arlington, Va.; Riverdale, Md.; 
Washington, D. C., and Siloam Springs, Ark. These, with its 
recorded occurrence in Missouri and Iowa, indicate a distribution 
similar to that of curculionis. 
It appears from observations made at Barnesville, Ga., in 1910 
that while practically all of the typical forms emerge from the 
earliest larvee, the variety rufus only reaches its full numbers very 
late in the season, after curculionis has ceased to appear. A few 
isolated specimens of rufus emerged in connection with the typical 
form from material from Elberta peaches, but most of them were 
—_—- oe 
