1921] Boving: Larvae and Pupae of Social Beetles 201 



a. Head larger than prothorax ; without ocelli ; 

 maxillary articulating area present, cardo 

 distinct; hypostoma normal (Plate IX, figs. 

 25, 33) Subfam. Prostominae 



b. Head as large as or narrower than pro- 

 thorax ; with ocelli ; usually having maxillary 

 articulating area and cardo fused into a 

 joint region, more or less amalgamated with 

 broad enlargement of hypostoma, 



Subfam. Laemophloeinae 



II. Mandible without molar structure or hypopharyngeal 

 chitinizations ; ventral mouthparts protracted ; gular 

 region large (Plate X, figs. 41, 42) Fam. Scalidiidae 



B. — The Subfamily Silvaninae. 



B. 1. — Systematic Description of the Subfamily Silvaninae 



Three pairs of legs. Fused tarsus and claw. Body orthoso- 

 matic, dorsally not plicate. Intersegmental membrane present. 

 Ninth abdominal segment small, ventrally reduced. Cerci not 

 developed. Tenth abdominal segment extending farther back 

 than ninth, conical, elongate, a locomotory organ. Holopneustic; 

 spiracles annular; first spiracle plainly mesothoracic. Head 

 porrect and exserted, or slightly invaginated. Clypeus large, 

 fused with frons. Labrum small, fleshy. Antenna two- 

 (three-) jointed, with large clavate second joint, very small or 

 indistinct apical joint. Mandible with flat, broad, molar part; 

 accessory condyle present; retinaculum hamate; apex tri- (or 

 quadri-) fid. Hypopharyngeal chitinizations strong, with paired, 

 ovate, large maxillular area carrying longitudinal series of long 

 setae. Ventral mouthparts retracted. Maxilla with cardo small, 

 transverse, in some forms distinctly bidivided ; stipes proximally 

 and internally attached to large maxillary articulating area ; mala 

 extending from distal end of stipes, large, simple, falciform, 

 terminated by single uncus ; externally to base of uncus with 

 small setose region, in some forms distinctly defined, being white 

 and membranous in contrast to otherwise brown and well chiti- 

 nized rest of mala. Maxillary palpus three-jointed. Labium 



