36 ENTOMOLOGY 



often bears a molar, or crushing, surface behind the incisive teeth. In 

 carnivorous species (B) the mandible is usually long, slender and sharply 

 toothed, without a molar surface. Often, as in soldier ants, the man- 

 dibles are used as piercing weapons; in bees (C) they are used for various 

 industrial purposes; in some beetles they are large, grotesque in form and 

 apparently purposeless. The mandibles of Onthophagus (D) and many 

 other dung beetles consist chiefly of a flexible lamella, admirably adapted 

 for its special purpose. In Euphoria (Fig. 265), which feeds on pollen 

 and the juices of fruits, the mandibles, and the other mouth parts as 

 well, are densely clothed with hairs. In the larva of Chrysopa, the 

 inner face of the mandible (Fig. 46, E) has a longitudinal groove against 

 which the maxilla fits to form a canal, through which the blood of 



PIG. 46. Various forms of mandibles. A, Melanoplus; B, Cicindela; C, Apis; D, Onthoph- 

 agus; E, Chrysopa; F-I, soldier termites (after HAGEN). 



plant lice is sucked into the oesophagus. In termites (FI) the mandi- 

 bles assume curious and often inexplicable forms. 



Next in order are the superlingua (maxillulcz) , which have been 

 overlooked or disregarded by most entomologists. The superlinguae 

 are well developed in Thysanura and Collembola, particularly the 

 former order. In Machilis, for example, the superlingua has essentially 

 the same structure as a maxilla, as appears in Fig. 47; in Japyx the 

 palpus is three-segmented (Hansen). The superlinguse, arising in the 

 embryo as a separate pair of appendages (Fig. 198, si), always become 

 united by their bases with the lingua (Fig. 198, In), forming a pair of 

 wing-like appendages on the dorsal side of the lingua (Figs. 50, 51). 



Among insects, superlinguae are best developed in Thysanura and 

 Collembola, and are known to occur also in Orthoptera, Dermaptera, 

 Isoptera, Corrodentia, nymphs of Ephemerida and larvae of some 

 Coleoptera. 



Hansen ('93) termed these appendages "maxillulae," regarding 

 them as homologous with the first maxillae of Crustacea; and in this 



