NO. 4 FEEDING MECHANISM OF LEPIDOPTERA SCHMITT J 



continuous with the parietal. In some cases the curved lateral part of 

 the proximal portion of the stipes is membranous, as in Cercyonia 

 alope (fig. 2 C). In others the lateral part is heavily sclerotized and 

 the tubular half is modified so that in effect there are two tubes set 

 side by side with membrane between. This arrangement is found in 

 the Pieridae (fig. 2F). The distal portion of the stipes is also re- 

 cessed under the parietal. The mesal surfaces of the maxillae bear 

 against each other or against a small projection of the labium. 



In addition to the muscles within the proboscis mentioned above 

 there are three pairs of maxillary muscles inserting on each stipes 

 and originating within the cranium. Two of these muscles originate 



antmcl 



Clp~ 



Fig. 3. — Proboscis extensor musculature. 



A, left half of head of Danmis menippe, showing interior by removal of eye. 

 B, right half of head, mesal view, of Thyridopteryx ephemeracjonnis (male), as 

 exposed by median sagittal cut. C, left half of head of Desiiiia juncralis, showing 

 interior by removal of eye. 



on the anterior arm of the tentorium, and the third originates on the 

 anterior part of the gena. Of the tentorial muscles, one arises on the 

 lateral surface of the anterior arm and inserts on the distal part of 

 the stipes, on the median flat sclerite. It is therefore called the anterior 

 tentorial proboscis extensor (fig. 3 A, atp). The second muscle origi- 

 nates on the mesal surface of the anterior arm of the tentorium and 

 inserts near the distal point of the stipes. Its origin on the tentorium 

 is always posterior to that of the anterior tentorial proboscis extensor, 

 so that the paths of these muscles cross within the head. This second 

 muscle is called the posterior tentorial proboscis extensor (fig. 3 A, 

 ptp). The genal muscle originates on the anterior part of the gena 

 and inserts on the flat mesal sclerite of the stipes. It is called the 

 cranial proboscis extensor (fig. 3 A, cp). 



