6o 



WALTER N. HESS. 



ward. Between this area and the secondary tooth there are 

 larger and stiffer setae. Those covering the remainder of the 

 surface are rather short and dense. Extending from the base to 

 near its tip is a tubular canal, through which digestive juices 



FIG. ii. Photurus pennsylvanica larva, labium, maxillae and lacinia, ventral 

 view. LP, labial palpus of labium; M, mentum of labium; SM, submentum of 

 Jabiuni; MP, maxillary palpus; ST, stipes of maxilla; Cd, cardo of maxilla; L 

 lacnia; G, galea. 



pass, while the larva is feeding. It does not open at the tip but 

 slightly caudad on the outer margin. 



The maxillae, labium and lacinia lie on the ventral side of the 

 head, and in these larvae they are fused into a flat fleshy plate 

 (Fig. n). When examined on its ventral side, the maxilla has 

 at its caudal portion a small triangular plate, the cardo (Cd), 

 which bears several short setae. Anterior to it is the large elon- 



