unimportant. The Danai, to which the fourth species from Aix (_Coliates Proserpina_) belongs, feed almost exclusively upon Leguminosæ, and these have recently been found in great abundance at Aix. Count de Saporta enumerates one species each of ?Trifolium, Caragana, Ervites, Sophora, Micropodium, Cercis and Gleditschia, two of Phaseolites and six of Cæsalpinites, belonging to the Papilionaceæ, besides nine Acacias and a Mimosa of the Mimoseæ, and four species of uncertain relations; making a series larger than he has found in any other family.[AI] Of these, two species of Phaseolites, one of Sophora, eight of Acacia and two of Leguminosites are specified as coming from the lower beds, where Coliates itself is found. But Coliates is most closely allied, as we have said, to a group of Indian forms, and the food plants of their caterpillars is almost wholly unknown. A species of Delias, however, to which genus Coliates has been specially compared, is stated to feed, not upon a leguminous plant, but upon Dioscorea, one of the Yam family; and the presence in Aix of a species of a closely allied group, _Smilax rotundiloba_ Sap., is announced by Count de Saporta. It is not improbable, therefore, that _Smilax rotundiloba_ was the food-plant of the larva of _Coliates Proserpina_.[AJ] The fifth Aix species is _Thaites Ruminiana_. It is most nearly allied to Thais of the present day, though it bears certain relations, as we have seen, to neighboring genera. Thais feeds principally at least upon Aristolochia[AK] and so, too, do Ornithoptera, Archon and some genera of swallow-tails; indeed, this seems to be a favorite food-plant with insects of this character. Parnassius, however, feeds on Sedum, Telephium, Sempervivum and Corydalis, especially on the first-named, one of the Crassulaceæ; but nothing very closely allied to this is specified by Saporta from Aix; neither, also is Aristolochia, but it has been found not only in Radoboj[AL] in the Mayencian, but also, according to Heer, at Hohe Rhonen in Switzerland, which belongs to the Aquitanian, and has at least one plant (_Laurus primigenia_ Ung.) in common with Aix. It seems, therefore, highly probable that either _Aristolochia nervosa_ Heer, _A. Aesculapi_ Heer, or a distinct species of the genus will yet be discovered at Aix,[AM] and may then be considered, as with little question, the food-plant of _Thaites Ruminiana_. If it be deemed hazardous to venture such an opinion, attention is called to the two following passages; the first is from the introduction to Heer’s paper on the fossil insects of Aix:[AN] “Dass indessen auch Weiden oder Pappeln [Populus] sich vorhanden, dürften der Bythoscopus muscarius und die Aphrophora spumifera [Homoptera] anzeigen, deren analoge lebende Arten besonders auf den Blättern und Zweigen dieser Bäume sich umhertreiben.” The second is a note in the errata to the translation of Heer’s work on the Climate and Vegetation of the Tertiaries[AO] by Gaudin: “Le Poacites