PROBABLE FOOD-PLANTS OF TERTIARY CATERPILLARS. 73 



A species of Delias, however, to which genus Collates 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 rotun- 

 diloba Sap., is announced by Count de Saporta. It is not improbable, therefore, 

 that Smilax rotundiloba was the food-plant of the larva of Collates Proserpina. 1 

 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 neighbor- 

 ing genera. Thais feeds principally at least upon Aristolochia 2 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 Crassulacese ; but nothing very closely allied to this is specified by Sa- 

 porta from Aix; neither, also is Aristolochia, but it has been found not only in 

 Radoboj 3 in the Mayencian, but also, according to Heer, at Hohe Rhonen in Swit- 

 zerland, which belongs to the Aquitanian, and has at least one plant (Laurus pri- 

 migenia 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, 4 and may then be considered, as with little 

 question, the food-plant of Thaites Ruminiana. If it be deemed hazardous to ven- 

 ture 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: 5 "Dass indessen 

 auch AVeiden oder Pappeln [Populus] sich vorhanden, durften der Bythoscopus 

 muscarius und die Aphrophora spumifera [Homoptera] anzeigen, deren analoge 

 Icbende Arten besonders auf den Blattern und Zweigen dieser Baume sich umher- 

 treiben." The second is a note in the errata to the translation of Heer's work on 

 the Climate and Vegetation of the Tertiaries 6 by Gaudin: "Le Poacites ciliatus 



1 Since this was written, Count Saporta writes me : ''Le genre ne saurait dtre mise en question, depuis qne nous avons entre les 



Smilax est nn des genres tcrtiaires les plus frequents. J'ai anssi mains tine superue empreinte de Radoboj (Aristolochia vemista 



signalcS dans le dcpot voisin de St. Zacharie ((Stage Tongrien infc- Sap.), qui denote line forme voisine des Arintoloches & feuilles 



rienrc [and therefore but slightlymore recent]) unc fenille qui m'a persiftantes et demi-coriaces, comme VA.reticulata Nutt. de Vir- 



paru devoir se ranger parmi les Dioscorees." ginie." Saporta, loc. cit., 342-3. 



An old writer in Fuessly's Magazin, writing from Italy, says <In a recent letter from Count Saporta he remarks : " Relative- 



that Thais feeds in tliat country upon Qucrcus. Five species of nient au Tluiites Jiuminiana, je n'ai pas encore decouvert a Aix de 



Quercus are known from Aix, but the statement in Fuessly'8 Mag- vestiges dn genre Aristolochin, mais ce genre devait y exitter." 



azin has never, to my knowledge, been continued. B Vierteljahrssrhrilt naturf. Gescllsch. Zurich, i. 12. 1856. 



* " Nous n'aTons pas encore rencomrt d'Aristolocbia dans les Ilecherches sur le Climat et In Vegetation du pays tcrtiaire, 



gypses d'Aix; mais 1'existenee du genre dans le tertlaire moyen 4to, 1861. 



