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XIII. Resting attitudes in some Lepidoptera, examples of 

 recapitulation in habit. By T. A. Chapman, M.D. 



[Read October 4th, 191G.] 



Plate LXXX. 



A chance observation, recently, led me to make a few 

 more that were available, and to the conclusion that the 

 facts examined gave some indications of being instances 

 of " recapitulation " ; * that is, of a habit or structure of 

 some ancestor, though now possibly useless, persisting 

 and having a place earlier in the development of the 

 individual than it had in the ancestor. 



The resting attitude of the great mass of the Heterocera 

 is with the wings in the same plane as that of the surface 

 on which the insect is resting. Even so there is a good 

 deal of variation, as, for example, in Noctuae there is the 

 flat position with the wings crossed as in Agrotis and 

 Noctua, or held in a pent-house position as in Taeniocampa 

 (Monima) and Plusia. 



As my observations were on Geometers it is more 

 apposite to note that in them the usual position is with 

 the wings laid flat on the surface, forming a triangle, the 

 inner margins being parallel with the body, either against 

 it or covering it. (PI. LXXX, figs. 1 and 3.) 



It is perhaps necessary to remember that, practically 

 without exception, after leaving the pupa and expanding 

 the wings, the Lepidoptera place the wings together vertically 

 over the back (in the resting attitude adopted by butter- 

 flies), in the larger species with the wings hanging down, 

 the insect resting on a vertical or overhanging object ; 

 so that gravity appears to be, and often is, necessary to 

 keep the wings straight whilst hardening and drying. 



* " Recapitulation " was the name given by Haeckel to the 

 theory that the ontogeny of the individual presented briefly in 

 series the evolution involved in the phyjogeny. It thus applies 

 properly to a succession of structures in the evolution, but one 

 habit or structure exhibited temporarily in the ontogeny repre- 

 senting a final habit or structure in an ancestor would have to be 

 classified under the same term. See Haeckel, " History of Creation " 

 (Ray Lankester), i, p. 309. 

 TRANS. ENT. SOC. LOND. 1916. — PARTS III, IV. (APRIL '17) 



