36 BRITISH MOTHS 



rule that no synonymous name ought subsequently to be given to a genus or species distinct from that of which it 

 is a syjionyme. In this case, however, the confusion would be greatly increased if it should be used, as Fabricius 

 gave the same name to a third species from Italy, which Laspeyres considered to bo identical with Tr. Chrysidi- 

 forme ; whilst Hiibner applied the same name in his Beytrage to a fourth species with opaque fore wings, which 

 he subsequently altered to S. Rhingiajforniis. Four distinct species have thus received the same specific name. 



TROCHILIUM, Scopou, (pars tvpica). 



{jEyeria, pars typica, Fabricius, Syst. Gloss. JEgeria, Stepliens ; (iurlis. Sesia p. Laspeyres; Ochs. ; God. &c.) 



This genus has the antenna; longer and more slender than in the preceding, gradually thickened from the base 

 towards the tip, which is suddenly acuminated and curved; the last joint being furnished with an apical pencil 

 of hairs ; in the males they are more or less ciliated or pectinated ; the palpi are longer than the head and 

 porrected ; the spiral tougue is nearly as long as the entire body, which is long and more or less slender, and 

 terminated by a fan-tail, varying in size and shape ; the wings are often more or less fenestrated or transparent. 

 In their habits they are equally distinct from the preceding genus, being exceedingly agile, and flying about in 

 the hottest gleams of the sun with the greatest activity amongst the leaves on which they occasionally settle ; at 

 such times elevating and depressing the body, and expanding or closing their fan-tails. 



I must refer to my observations upon the family and preceding genus for the reasons which induce me to 

 adopt Scopoli's name for these insects, and to retain them as a single genuj. 



Some of the species differ from the remainder in having the fore wings entirely clothed with scales ; and it 

 has been proposed to form them into a distinct genus (Memythrus Newm. Sph. Vesp. p. 5.3). But such a step 

 appears to me to be unnatural, because it happens that in an American species the males have the fore-wings 

 fenestrated, whilst in the females they are opake. (iEgeria exitiosa Sa>/, an insect exceedingly destructive to 

 peach-trees.) Jlr. Newman denied the correctness of this fact, which has, however, been confirmed to me both 

 by Mr. E. Doubleday and Dr. Harris, to which latter gentleman I am indebted for specimens. Analogous to what 

 has already been mentioned as occurring in the clear-winged Sphingidoe, Laspeyres mentions the interesting fact, 

 that when these insects first leave the pupa case, their wings are not hyaline, but are clothed with a fine powder, 

 which rubs off with the greatest facility. 



The species are rather numerous, and have been formed into six genera, by Mr. Newman. It appears to 

 me more natural to adojit the sections which are given by 3Ir. Stephens, which, indeed, rest upon comparatively 

 and equally slight characters. 



" A. Antenna- much shorter than the body, in the males distinctly pectinated, anterior wings nearly clothed 

 with scales; abdomen robust." (Memythrus, Newman. Par.anthrene, Hiibner ; Newm.) 



