122 THE entomologist's record. 



Sesiidae or /Cgeriidae. 



By LOUIS B. PEOUT, F.E.S. 



My friend Mr. E. W. Lane, who is doing such excellent work at 

 the " Clearwings," and other entomologists, have more than once 

 asked me concerning the complications of their generic nomenclature. 

 The Nomenclature Kevision Committee of the North London Natural 

 History Society a few years ago accepted Mr. Kirby's nomenclature 

 (ride, h'ntoiii., xxxvi., p. 61) but neither he nor they have published 

 any exhaustive explanation of the processes by which the result was 

 arrived at. The question is one of quite exceptional difficulty to deal 

 with, without bringing in that most dreaded personal element suggested 

 in the statement " I therefore choose " — this or that — in other words, 

 procedure in the past has been so unmethodical that it seems almost 

 impossible to apply rigidly and unswervingly the "historical method." 



Seiiia was erected by Fabricius in 1775 for a heterogenous assemblage 

 of bee-hawks and clear-wings which I need not enumerate ; but it is 

 important to note his diagnosis: "Palpi rellexi. Lingua exserta, 

 truncata. Antennae cylindrical extrorsum crassiores." "Lingua 

 truncata " seems to preclude the Sphingid section from being typical, 

 although I am aware that — bearing in mind the very vague and loose 

 generic diagnoses of the period — it is generally dangerous to over-press 

 arguments based thereon. 



MacroiilosHum was erected by Scopoli two years later with type 

 Htdlatarinii, and Troclnlirun with no type specified; we know from the 

 whole plan of Scopoli's work at the Heterocera, that these were meant 

 to cover sections E and F of the "Vienna Catalogue," i.e., that Macro- 

 (/lossKiii included stellataniin and (icnothcrae [proserjnna, Pall.), and 

 Trochiliinn the clear-winged species, including fnciforiiiis and boiiibi/li- 

 foniiis. The two new genera therefore covered, for all practical 

 purposes, the Senia of Fabricius, with which Hcopoli appears to have 

 been unacquainted ; to argue that Scopoli's action constituted some 

 non-European species the type of Sesia seems to be, as Sir George 

 Hampson has justly remarked, a reductin ad abnurduiii. 



Of course Scopoli's action did not really influence Fabricius' genus 

 in any possible way; it is most important that work at generic nomen- 

 clature should not be disfigured with arbitrary assumptions that two 

 authors workmg quite independently are restricting one another's 

 genera ; the only conceivable case in which this could happen (auto- 

 matically) is where two new genera absolutely and explicitly cover the 

 same ground as one old one, and it is necessary (upon present-day 

 ideas) to conserve the old name for the later of the two new genera, 

 in order to give " priority " in the earlier of the two, its due weight. 

 Even here, however, it is hard to see how we can sit in judgment on 

 our predecessors, where they have failed to comply with this present- 

 day requirement, and permit ourselves to rule them "out of order;" 

 surely the most we can say is that they oiKjht to have done otherwise, 

 hut tlu'ij did not. 



The above is a slight digression, in order to ventilate a very impor- 

 'tant question ; let us now return to our historic sketch. 



In 1797 Cuvier cited stellatariiDi as an example of .SV.s/rt ; this would 

 make it the type, but for its disagreement with the generic diagnosis 



