1020 Wisconsin Academy of Sciences, Arts, and Letters. 
described by Stingelin (’06) and regarded by liim as identical 
with Herrick’s species. This conclusion is probable, especially 
in view of the close relation between the fauna of the southern 
United States and that of South America, but it is not certain. 
Herrick’s sketch of the antenna of P. tridentata is very care¬ 
fully drawn, apparently with the aid of a camera lucida. It 
shows that the 3-jointed ramus is two-thirds as long as the 
other and bears five nearly equal setae. In Stingelin’s draw¬ 
ing this branch is much shorter and bears four setae of very 
different size, like those of P. bidentata. Ho emphasis should 
be laid on the difference in number of setae. There is full 
warrant for Stingelin’s remark (’06, p. 4, footnote) on the dif¬ 
ficulty in determining the number of antennary setae. Those 
of the 3-jointed ramus, especially, break off very easily and 
leave no trace. Daday (’04, p. JL'l; ’05, p. 218) makes the 
possession of four setae on this branch of the antennae a char¬ 
acteristic of his genus Parasida, while Herrick assigns five 
setae to his species P. bidentata. My specimens confirm Her¬ 
rick’s statement; but the setae are of very different size and 
one or more are often absent. Probably not more than 20% 
of the 100 or more individuals of P. bidentata that I have 
examined possessed 5 setae. Their number, therefore, can¬ 
not well be used as a differential specific or generic character. 
Since Herrick’s papers are indispensable to any student of 
American entomostraca it may not be out of place to say a 
few words regarding his manner of work, as shown by com¬ 
paring his note-books with his published papers. Probably no 
modern writer on entomostraca has done so much good work in 
a way so exasperating as has Herrick. He collected and de¬ 
scribed widely; he had a good eye for the general situation; 
and is usually right in his statements, as far as they go. But 
his descriptions are uncritical and often so incomplete that they 
tell little about the species. It is usually easy, however, to 
recognize his species when they are rediscovered, as was the 
case with P. bidentata. The note-books which I have show 
clearly his method of work and also the source of the vague 
and unsatisfactory nature of many of his figures and descrip¬ 
tions. He made many sketches while on his collecting trips 
