28 



ENTOMOLOGY 



Meloe has just been mentioned. In Sminthurus malmgrenii (Collem- 

 bola) the antennae of the male are provided with hooks and otherwise 

 adapted to grasp those of the female at copulation. 



Though systematists have recorded many instances of antennal 

 antigeny, the interpretation of these sexual differences has received very 

 little attention; though a beginning in the subject has been made by 

 Schenk, whose results will be referred to in connection with the sense 

 organs. 



Mouth Parts. On account of their great range of differentiation, 

 the mouth parts are of fundamental importance to the systematist, par- 

 ticularly for the separation of insects into orders. Most of the orders fall 



A O B 



FIG. 43. Antennae of mosquito, Culex pipiens. A, male; B, female. 



into two groups according as the mouth parts are either biting (mandibu- 

 late) or sucking (suctorial). Collembola and Hymenoptera, however, 

 combine both functions; Diptera, though suctorial, exhibit various modi- 

 fications for piercing, lapping or rasping; Thysanoptera are partly man- 

 dibulate but chiefly suctorial; and adult Ephemerida and Trichoptera 

 have but rudimentary mouth parts. 



The mandibulate orders are Thysanura, Collembola (primarily), 

 Orthoptera, Platyptera, Plecoptera, Ephemerida (rudimentarily in adult), 

 Odonata, Neuroptera, Mecoptera and Coleoptera. 



The mouth parts of an insect consist typically of labrum, mandibles, 

 maxilla, labium and hypopharynx (Fig. 44), though these organs differ 

 greatly in different orders of insects. The mandibulate, or primary type, 



