i84 LEPIDOPTERA. 



closely allied species have, by mere accident, been placed 

 far apart. The number of species really devoid of any such 

 crests is large, but even of these a few have colour-imita- 

 tions on the back of the abdominal segments. 



All these structural appendages seem to be useful in 

 characterising genera, yet neither of them appears to be so far 

 dominant as to assist in the division of the whole group into 

 sections. The arrangement of genera worked out by Lederer, 

 and adopted in Drs. Stau dinger and Wocke's Catalogue, is 

 based on many of these characters, and in many respects is 

 an admirable classification, but some of its genera are pon- 

 derous, and I think unnecessarily mixed. The structural 

 characters furnished by Mr. Hampson in his fine work on the 

 " Moths of India " are extremely clear and valuable, and have 

 been of very great help to me ; but both arrangements seem, 

 in my opinion, to be damaged by the inclusion of the Gyma- 

 toplioridce among the Notodontidce and their exclusion from 

 the present group. The structure and usefulness of the tongue 

 in the Gymato'plioridce,, their love of sweet substances as food, 

 and their crepuscular flight, are characters so diametrically 

 opposite to those of the Notodontidce, and so entirely in accord 

 with those of the Noctum, that I feel it necessary to follow 

 Stainton in including them in the latter, and in placing 

 them at the head of the family, as a stepping-stone from 

 the BombyciTia, to which they, undoubtedly, are in some 

 respects allied. 



Having indulged in a somewhat prolix apology for my 

 attempt to produce an arrangement of this group differing 

 in some details from those at present in use, it only remains 

 to point out that the specific distinctions — although the species 

 are so closely allied, and in some cases very variable — are 

 usually easy of recognition and quite reliable, and that they 

 depend largely upon modifications of a certain plan or pattern 

 of markings in the fore wings ; also, that by the use of a 

 definite nomenclature for these markings much of the con- 

 fusion and difficulty of description, and discrimination, of 



