l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 97 



Pump of Lepidoptera. — Snodgrass (1935) has shown that the suck- 

 ing pump of moths and butterflies inchides at least the buccopharyn- 

 geal region of, the stomodaeum. This is evidenced by the fact that the 

 dilator muscles of the pump are inserted both before and behind the 

 connectives of the frontal ganglion, which lies on the dorsal wall of 

 the pump. The sucking pump of a butterfly, Danaus menippe, is il- 

 lustrated in figure 8 B showing the dilators of the true pharynx in- 

 serted on the posterior portion of the pump. Whether the cibarium or 

 any portion of the food meatus is also incorporated in the lepidopterous 

 sucking pump has therefore been an open question. 



The labrum {Lr) of moths and butterflies is usually described as a 

 narrow transverse band at the lower edge of the clypeal region, bear- 

 ing the pilifers {Plf) on its lateral extremities (fig. i B). In orthop- 

 teroid insects there is a pair of muscles, the compressors of the labrum 

 {cplr), originating on the anterior wall of the labrum and inserting 

 on the epipharyngeal wall. If the small lobe between the pilifers is the 

 labrum, as it appears to be, this pair of muscles exists in the Lepidop- 

 tera (fig. 8 B and 9B), and the cibarium then necessarily forms part 

 of the anterior section of the pump. 



However, there is certain other evidence that the cibarium is in- 

 cluded in the pump, based on the structure of the floor of the pump. 

 At the base of the salivary meatus in many generalized insects there 

 is a small cuplike depression or pocket into which the median salivary 

 duct pours its secretions. This pocket is known as the salivarium 

 ( fig. 8 A, Slv) . It is supplied with three pairs of muscles, a dorsal pair 

 (is) arising on the suspensorial sclerites of the hypopharynx, and two 

 ventral pairs, arising on the prementum. In the Lepidoptera, only the 

 dorsal pair of muscles, arising on the hypopharynx, may be found. 

 Their point of origin is on the floor of the sucking pump (fig. 9 A, B) 

 showing that the anterior part of the floor is derived from the hypo- 

 pharynx and therefore that this portion of the sucking pump belongs 

 to the cibarium. 



In orthopteroid insects the hypopharynx has a pair of retractors 

 (fig. 8 A, rhphy) originating on the tentorium. In a geometrid moth, 

 Haematopis grataria (fig. 5 A), a pair of muscles was found insert- 

 ing on the floor of the pump and originating on the anterior arms of 

 the tentorium. Since the ventral dilators of the true pharynx in 

 orthopteroid insects pass between the circumoesophageal connectives, 

 they could not possibly migrate from the tentorial bridge to the an- 

 terior arms. Hence, this pair of muscles in Haematopis must repre- 

 sent the retractors of the hypopharynx, and although they may have 

 migrated beyond the limits of hypopharynx, their presence, neverthe- 



