72 MONOGRAPHIA ^GERIARUM ANGLI.E. 



Other families which I have arranged in the same natural 

 order. I am inclined to believe that many genera, formerly 

 intervening, have become extinct, or are yet undiscovered : the 

 most marked hiatus is between the JEgertidce and the Zeuze- 

 rklce, the central Cossidce being evidently, though not nearly, 

 related to both of them ; to the ^geriidce, by similarities in 

 the palpi and antennae ; to the Zeuzeridre, by similarities in 

 the antennas, legs, and wing nervures, and by the total want 

 of mouth. 



Another family having been formerly coupled with the one 

 now under consideration, by one of the most talented ento- 

 mologists that this or any other country has ever produced, I 

 must not pass it by quite unnoticed. I allude to the genus 

 Zygcena of Fabricius, included, by Dr. Leach, with JEgeria, 

 under the name ZygcBnidce; and Mr. Samouelle, compiling 

 from Dr. Leach's papers, in his Compendium, assigns as a 

 character to the family, " palpi long, separate, covered with 

 long scales, or porrected hair.""* These characters apply but 

 very indifferently to Zygcena ; and its whole habits and eco- 

 nomy' are at variance with those oi JEgeria. 



Such, then, are the characters, and such the relations, real 

 and supposed, of the family j^geriidcc. After all, so weak 

 are the bonds of alliance, — so far removed the only supposable 

 approaches, that the family must be considered one of the 

 most isolated that natui'al history affords ; and as such I will 

 now consider it, and only treat of it in relation to itself. 



Following out the Septenary System, we look for a type or 

 centre, around which to arrange all the species we ai-e at pre- 

 sent acquainted with. This offers, in SpJiinx A/nformis"^ of 

 Linnaeus ; and consequently, a genus to contain that species 

 must be central, and six other genera arranged round it, or 

 vacancies left should a deficiency appear. I fear there are 

 those who will disapprove of further generic division in this 

 family: but I think I have from the first been tolerably re- 

 gardless of the opinions of others, and it is now too late to 

 swerve from my object in order to propitiate private favour ; 

 and I would wish those who are ever ready to cavil on this 



'' Entomologist's Useful Compendium, p. 244. 

 ' Sphinx Vespiformis, pp. 35, 36. 



" When the Septenary System is thus reduced to units, as I may say, I find 

 the largest species is invariahly the type or centre. 



