NO. 4 FEEDING MECHANISM OF LEPIDOPTERA — SCHMITT 



19 



less, is evidence that the hypopharynx is incorporated in the sucking 

 pump. In an oecophorid, Agonopterix sp., a similar pair of retractors 

 occurs. 



The highest development of the sucking pump is to be found in the 

 Sphingidae, the Noctuidae, and especially in the butterflies. Dilation 

 of the pump is produced by the muscles originating on the wall of the 

 head ; contraction in the lower moths is produced by the intrinsic elas- 

 ticity of the pump itself, but in the above-named groups, bands of 



Fig. 9. — Various structural details of the head. 



A, cross-section of sucking pump of Danaus nienippe. B, mesa! view of right 

 half of head and base of right proboscis unit of Papilios'p. C, ventral view of 

 salivarium of Lycaenopsis argiolus. D, base of proboscis and sucking pump of 

 Papilio sp. as seen from right side. E, left half of head of Haematopsis grataria, 

 showing interior by removal of eye. 



muscles passing around the pump are mainly responsible. The " floor " 

 of the pump is heavily sclerotized and well braced to withstand the pull 

 of the dilating muscles. Figure i shows the pump in a specimen 

 cleared in KOH, with a portion of the dorsal wall of the pump re- 

 moved. The infolded ridge on each side between the parietal and the 

 clypeus can be seen passing under the floor of the pump (HphyR), 

 thus providing support. Morphologically, these ridges are more diffi- 

 cult to trace. Figure 9 D shows the bracing arrangement of the pump 

 of a butterfly, Papilio sp. The infolded ridge between the clypeus 



