MIGRATION" AND DISPERSAL OF INSECTS : LEPIDOPTERA. 233 



Geometrid genus'' — is not accepted, although it seems to be founded 

 on quite sufficient pecuharities ; nor are Scudder's groupings in 

 Aripjnnis, nor (to any adequate extent) in the Blues, followed ; on the 

 other hand, the necessary splitting up of Theda into three genera 

 {Tlu'cia, Callophri/a, and Zephi/nis) has apparently been deemed 

 inevitable, as also has the removal of hiiperantus from the genus 

 Kpini'pluii' (into Ajihantopaa, Wllgrn.). Hampson's work, so far as 

 published, has been requisitioned for the Syntoinids and Lithosiids, as 

 well as for the I'j/ralidac, and Meyrick's revision has had some 

 influence in the (Tcouietridae, kc. Mr. Tutt's Urithli, J.cjiidnptcra, 

 vol. ii., was no doubt received too late for the close study which it 

 requires, and the treatment of the Psycbids is a kind of compromise 

 between the systems of Heylaerts (mentioned as authority in the 

 preface, dated December 31st, 1900) and of Tutt. The latter, based 

 as it is upon the splendid work of Dr. Chapman, may be trusted to 

 win its way in all essentials so soon as it is thoroughly known and 

 digested. Already one is glad to see much of the corrected nomencla- 

 ture accepted according to Tutt, and some of his most obviously 

 necessary genera — Lujfia, Bankenia, &c., duly recognised. 



* For Erehomorpha, Ehves, nee Walker, the name of BoeJ>cria,n. nom., should 

 be substituted, in honour of the discoverer of the type species, which is puDiienio, 

 I)oeb. 



(To be continued.) 



Migration and Dispersal of Insects : Lepidoptera. 



By J. W. TUTT, F.E.S. 



The tropical and subtropical forests of Central and South America 

 appear to produce several migrating species of lepidoptera. In the 

 openings of these great forests insects abound. Here giant trees 

 throw up their great crowns and form a canopy of foliage that almost 

 shuts out the light, whilst the twining lianas hang rope-like from the 

 branches, entangling the massive trees like cables or covering the dark 

 leafage with their beautiful flowers ; epiphytes may be seen in every 

 fork sending down their long aerial roots, and great broad-leaved 

 heliconias. leathery melastoniie and succulent begonias are abundant, 

 whilst the cecropia trees, with white stems and large palmate leaves 

 form huge candelabra, and the ground is sometimes carpeted with 

 large flowers, yellow, pink, or white, that have fallen from some 

 invisible tree-top above, or the air is filled with a delicious perfume, 

 the source of which one seeks around in vain, for the floAvers that cause 

 it are far overhead out of sight, lost in the great overshadowing crown 

 of verdure. It is on the outskirts of such forests as these, so 

 ex(iuisitely described by Belt, that insect life is most prolific, and this 

 powerful writer briefly chronicles (Xatitndii^tt in Xicaraf/iia, p. 152) 

 the migrating habits of certain species. He writes: " As we rode along, 

 great numbers of a brown-tailed butterfly {Tiinctes cliinnt) were flying 

 to the south-east ; they occurred, as it were, in columns. The air 

 would be comparatively clear of them for a few hundred yards, then 

 we would pass through a band, perhaps 50 yards in width, where 

 hundreds were all in sight, and all travelling one way. I took the 

 direction several times with a pocket-compass and it was always south- 

 east. x\mongrft them were a few yellow butterflies, but these were not 

 as numerous as in former years. In some seasons these migratory 



