32 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I42 



On emergence of the pupa the new antenna (fig. 15 H) is five times 

 the length of the larval antenna (G), and is distinctly differentiated 

 into scape, pedicel, and a multiannulate flagellum, but its surface is 

 entirely devoid of hairs. During the pupal stage, the epidermis con- 



BCD 



Fig. 15. — Examples of larval antennae, and developmental stages of a 

 mosquito antenna. 



A, Palpares sp., Neuroptera-Myrmelionidae. B, Corydalns cornutus, Mega- 

 loptera. C, Chironoinus plumosus, Diptera-Chironomidae. D, Bombyx mori, 

 silkworm. E, Same, apical part of antenna. F, Trogodcrma sp., Coleoptera- 

 Dermestidae. G, Culex sp., mosquito, left antenna of larva, dorsal. H, Same, 

 pupal antenna, same magnification as G. I, Same, part of pupal antenna with 

 adult antenna formed inside the cuticle. J, Same, adult female antenna, same 

 magnification as G and H. 



tracts to a slender, jointed shaft w^ithin the cuticle (I), having all 

 the hairs and bristles of the adult antenna (J). 



VI. THE TENTORIUM 



The tentorium is an internal cuticular framework of the head of 

 ectognathous insects formed by ingrowth and union of four apodemal 

 arms from the exoskeleton. Two of the arms are anterior, and two 

 posterior. The posterior arms arise at the lower ends of the postoc- 

 cipital sulcus and usually unite with each other to form a transverse 



