BIOLOGY OF SOME COMMON LAMPYRID^. 6l 



gated stipes (St), which also bears several long bristles and many 

 shorter setae. Anterior of the stipes on the external side is a 

 stout four-segmented palpus, the maxillary palpus (MP), 

 bearing several forward projecting setae. At the side of the 

 maxillary palpus, internally, is the two-segmented galea (G) of 

 the maxilla, which resembles very much in appearance a two- 

 segmented palpus. Beside the galea, internally and also extend- 

 ing a short distance along the stipes, is the rather dense chitinized 

 flattened lacinia (L). Both the galea and lacinia bear many 

 setae, and along the inner margin of the lacinia is a row of rather 

 stiff bristles. The tip of the galea ends in short setae, which 

 probably function as specialized sense organs. 



On the ventral side of the labium, the submentum (SM) 

 appears much elongated and it lies in 

 the central region of the mouth-parts. 

 It bears numerous short setae and a few 

 long bristles. The mentum (M) is in 

 the form of a thickened bi-lobed struc- 

 ture, from which project anteriorly the 

 two-segmented labial palpi (LP). Both 

 structures bear a considerable number 

 of anteriorly projecting setae and bris- 

 tles. On the underside, the sclerites of FIG. 12. Photums pennsyi- 

 the maxillae, labium and lacinia are in- vanica larva - hypopharynx. 



... ... . dorsal view. 



distinct, though in this region there are 

 numerous small anteriorly projecting setae. 



The hypopharynx (Fig. 12) is triangular in shape with the 

 anterior portion bi-lobed. It is entirely covered with a dense 

 mass of anteriorly projecting setae, except along its basal portion. 

 The setae of the anterior half are much denser and longer, and 

 many of them are branched. 



From the previous description of the mouth-parts, it is evident 

 that there are numerous setae projecting forward inside of the 

 mouth region. These setae, according to Haddon (1915) and 

 Vogel (1915), function as a strainer in preventing all except 

 liquid food from entering the mouth. 



In the pharynx region there are several heavily chitinized 

 plates to which numerous muscles are attached, and which, 



