August, '16] 



PIERCE: HABITS OF POLYDRUSUS 



427 



Larva. — Creamy white with head slightly yellowish, but very little darker than 

 the body. Mandibles and edge of frons darker. Length 4-6 mm. Body bristling 

 with long setae. 



Head deeply, triangulately, emarginate at middle. Mandibles bluntly two- 

 toothed. Margin between labrum and clypeus (post-labrum Lyonet 1762) faint. 

 Antenna? minute, ovoid. Maxillary palpi minute, two-jointed. Labium broad obtuse, 

 rounded at sides, terminated by a thin chitinous 

 bow at base of stipes labii, palpi two-jointed, 

 small, terminated by long setae. Frons trian- 



Fig. 28. Polydrusus impressifrons Gyll. 

 Face of larva and dorsal aspect of larval head. 



Fig. 29. Polydrusus impres- 

 sifrons Gyll. Side view of lar- 

 val head and ventral aspect of 

 apex of abdomen. 



gular, with one pair of long, very fine setae. 



Epicranium with three pair of fine setse along 



frontal suture and with two posterior setse. 



Thorax and abdomen provided with many long setse. Spiracles indistinct. The 



last segment is almost circular with the anal opening in the center and this is 



placed slightly in front of the apex of the abdomen. The next to the last segment 



has four long distant dorsal setse and four approximate finer ventral setse. 



Pupa. The pupa is characterized especially by the broad two-pronged apical 

 segment. 



Color creamy-white, eyes black. Length 4.5 to 5 mm., breadth 1.25 mm. Dorsally 

 and laterally sparsely bristling with setigerous tubercles. Beak short, robust, 

 enlarged at manchbles, near median line with three pair of setse. Eyes placed 

 closer together than width of beak. Between and above each eye are four setae 



