754 Wisconsin Academy of Sciences, Arts , and Letters. 
in the greater diameter. Peck stated that in his 
collection on Ambrosia trifida L. they were 35— 
60 microns long. (35th Report, p. 138.) In my 
first specimens on Ambrosia artemisiaefolia L. the 
spores were 55—80 microns long but a later col¬ 
lection on this host showed spores of about the size 
of those on Bidens. This collection consisted of 
a single gall on a plant growing in a roadside 
ditch with infected Bidens. This was the only 
instance in which I have seen the fungus on 
both host genera at one station. Altogether the 
range of spore length is from 30—80 microns 
which is just the range given for the spores of 
Protomyces macrosporus Ung. of Europe which 
however appears to be confined to Umbelliferae 
and to be unknown in America, the citation of 
that species in my first supplementary list having 
been based upon error as to both fungus and host. 
Specimens on Bidens cernua L. growing in very 
loose peaty soil have galls upon the roots also. 
Recent authors place Protomyces in Hemias- 
CINEAE. 
Prof. E. W. Olive has kindly furnished the following list 
of species of Empusa collected by him in the vicinity of Madi¬ 
son and specimens of which are in his collection. 
666. Empusa Americana Thaxt. 
On a blue bottle fiy. Madison. (Olive.) 
667. Empusa aphidis Hoffman. 
On various aphides. Madison. (Olive.) 
668. Empusa cueicis A. Braun. 
On Gliironomus sp. indet. Madison. (Olive.) 
669. Empusa muscae Cohn. 
On house flies. Madison. (Olive.) 
670. Empusa rhizophora Thaxt. 
On caddis flies. Madison. (Olive.) 
671. Empusa sciarae Olive. 
On Sciara sp. indet. Madison. (Olive.) 
