THE ENTOMOLOGIST 



Vol. XLVI.] JULY, 1913. [No. 602 



FxECES EJECTOR OF LEPIDOPTEROUS LARV^. 



By F. W. Frohawk, M.B.O.U., F.E.S. 



(Plate X.) 



Certain lepidopterous larvae are provided with a remarkable 

 comb-like apparatus for the forcible ejectment of their excreta, 

 which probably is most highly developed in the Hesperidae. 



This organ has been referred to by Dr. 0. Hofmann in his 

 description of Secaphila minusculana, published in the * Entomo- 

 logist's Annual,' 1873, p. 62; stating :—" Immediately behind 

 and under the anal plate, exactly above the anal opening, is a 

 small semicircular plate of black chitine, about half the size of 

 the anal plate itself, which is extended posteriorly in six long 

 black thorns, and probably has for its object to assist in the 

 evacuation of the excrement. This formation is entirely wanting 

 in the closely allied S. wahlhomiann, but, on the other hand, it 

 occurs again in the closely allied commiinana and virgaurana." 

 Also, in 'Novitates Zoologicse,' vol. xvi. p. 831, Dr. K. Jordan 

 describes and figures 'the anal comb or fork which he and the 

 Hon. Walter Rothschild found in the larva of Somahrachys. In 

 all the specimens examined each had either three or four tines ; 

 these, he states, were " always practically of equal length. They 

 vary in shape, inasmuch as some are pointed and others truncate 

 and dentate. . . ." Dr. Jordan also adds : " We ascertained its 

 use by observing the live larva under a lens. When the fieces 

 leave the anus the rake is employed to push them outside, and 

 give them a final jerk, which sends them rolling off the anal 

 segment." 



In the life-history of Carterocephalus palcemon, which I pub- 

 lished in the ' Entomologist,' 1892, vol. xxv. p. 256, I noted the 

 fact that the larva of this species " has the power of casting its 

 excrement sideways with considerable force, as if propelled by a 

 spring, sending it a foot or more, which undoubtedly is a means 

 to prevent fouHng its domicile." This habit, I have noticed, is 

 common with the Hesperidae larvae. 



BNTOM. — JULY, 1913. Q 



