INSECTA. 397 



with only ten feet, the rest with twelve, always with anal feet. 

 Pupa inclosed in a thin follicle. 



The genus Phalcena or Geometra is principally characterised by 

 the caterpillars ; since these have no feet in the middle of the body 

 they move in creeping, as leeches do, by flexion and extension of the 

 body. Hence these caterpillars are named surveyors or span-cater- 

 pillars (erucce geometricce, chenilles arpenteuses, Spanner.) 



Comp. on this genus TREITSCHKE especially, Die Schmetterlingen von 

 JSuropa, of which the entire sixth part (Leipz. 1827, 1828) is set apart for 

 treating of the numerous European species of this genus ; and further 

 HERRICH-SCH^EFFER, Uebersicht der Spanner, in his continuation of PANZER, 

 Ins. Deutschl. Heft 165, 176, 179. 



has made a subdivision according to the antennae ; where they 

 are pectinate he gives to the specific name the termination -aria (as pini- 

 aria), when they are setaceous that of -ata (as grossulariata 1 ). The cha- 

 racteristic of pectinate antennae, however, besides that it is proper to the 

 male alone, occasionally separates naturally allied species. As little can 

 the separation of these species, which have wingless females, of which 

 LATREILLE forms his sub-genus Hybernia, be commended. 



a) Caterpillars with twelve feet. 



Ellopia TREITSCHKE. (Antennae in males pectinate.) 



Sp. Phalcena margaritaria FAB., Phalcena margaritata L. fern., SEPP, Nederl. 

 Ins. n. Nachtvl. n. Bende i Gezin, Tab. in., PANZ. Deutschl. Ins. Heft 41, 

 Tab. 23, Heft 63, Tab. 23 ; light-green wings, the fore with two white 

 bands, the hinder with one only, which is a continuation of the most 

 external of the fore- wing. Amongst the Noctuce also some species occur 

 with twelve-footed caterpillars, which however are not spanners. 



6) Caterpillars with ten feet. 



Ennomos, Accena, Geometra, Aspilates, Crocallis, Gnophos, Boar- 

 mia, Amphidasis, Psodos, Fidonia, Chesias, Caber a, Acidalia, 

 Larentia, Cidaria, Zerene, Minoe, Idcea TKEITSCHKE (a name to 

 be rejected since already given by FABKICIUS to a genus of the 

 Diurnals). Comp. on other genera, here omitted, WESTWOOD, Generic. 

 Synops. pp. 98 104. 



[Note. The numerous species of Phalcence are distinguished by variety 

 of form, and often present an analogy truly wonderful with other genera 



1 Here we have an instance of the happy mnemotechnic of which LINNJSUS in all 

 his writings made such rational use. The distinction however given by him is not in 

 every instance well-founded ; Phal. sambucama, for example, ought properly to be 

 called sambucata. 



