mark (E. B. Hoffmeyer coll.) from a locality about a hundred miles from the type locality of similis.
PARASITE.—Platygaster instricator (acc. Hennequy 1904).
Adler discovered this insect as a result of his experimental breeding from the agamic longiventris in the spring of 1880. He found the adults emerging from the galls in May, about two weeks before he secured adults of the bisexual form of folii in that same year. But since Adler's single record seems to be the basis of all the other published emergence data for substituta, and since the Danish material in my collection (Hoffmeyer coll. and det.) is dated as late as May 31, June 2, and June 4 while taschenbergi distributes its emergence from May 25 to June 11 even in Denmark (not far from Adler's locality in Germany), we are unwarranted in concluding (as previous literature does conclude) that there is any great difference in the emergence dates of the two insects.
Adler saw substituta oviposit to give rise to the agamic longiventris only by an accident in connection with his experiments on the succession of taschenbergi and folii. In 1876 he placed what he took to be taschenbergi adults on the leaves of an oak from which he later secured galls of longiventris. His further work on longiventris having shown the very close similarity of both galls and insects of taschenbergi and substituta, we may conclude that Adler had really discovered the alternation of our present species. The data are, however, scant enough to encourage some one in Europe to repeat the work.
The gall of substituta is said (Adler 1881 and Hieronymus 1890) to differ from that of taschenbergi in nothing more than the few characters which I have given above. Adler considered that the insects of the two could be distinguished by the leg coloration which I have noted (with corrections) above. Mayr (1882) put taschenbergi, flosculi, similis, and verrucosa in a single paragraph with a remark about “Die hierhergehörenden Arten, welche ich nicht sicher zu unterscheiden im Stande bin …,” meaning that he was unable to distinguish these insects; but the Kieffer (1901) and Dalla Torre and Kieffer (1910) monographs arrive at the conclusion that these bisexual insects are indistinguishable. I have only six adults of similis, but eighty-five adults of taschenbergi, and it seems to me that every one of the females can be distin-
