NO. 4 FEEDING MECHANISM OF LEPIDOPTERA SCHMITT 



13 



proboscis musculature. In the large moth Samia cecropia, for ex- 

 ample, the proboscis is represented by two small shapeless lobes (fig. 

 II B, Prh), associated with which there is a single pair of tentorial 

 muscles. The position of these muscles suggests that they may be the 

 posterior tentorial proboscis extensors. 



Prh P^^^ »^P V^P /K 



PrK 



Fig. 6. — Proboscis extensor musculature. 



A, left half of head of Catocala nubilis, showing interior by removal of eye. 

 B, same of Darapsa pholiis. C, right half of head, mesal view, Apantesis virga, 

 as exposed by median sagittal cut. D, same of Malacosoma americana. 



The tentorium of this moth has developed a peculiar secondary 

 function. In addition to having the anterior part of the anterior arms 

 thin-walled and bulging, displacing blood with air, the posterior part 

 of the anterior arms is tubular and curved to provide a sort of cradle 

 for the brain and suboesophageal ganglion. This is done by having 

 each arm pass between the brain and the optic lobe on its side. If it 

 were not for this the brain would be supported only by the optic lobes. 



In other saturniids remnants of one or both pairs of the tentorial 

 proboscis muscles can be found, but the cranial proboscis extensor is 



