382 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 39. 



DESCRIPTION OF THE MOUTH-PARTS. 



Female. — Mouth-parts close to the second antennae; labrum much 

 wider than long, not prominent, in Txniacanthus reduced to a very- 

 small size; labium reduced to a mere ridge on the ventral surface of 

 the head. Mandible three-jointed, the basal joint fused to the surface 

 of the head, second and third joints free and turned backward; third 

 joint consisting of one or two slender spines of equal length, shorter 

 than the second joint. Maxillary hook in the form of a claw similar 

 to those in the Caliginse and attached to the ventral surface near the 

 lateral margin and just behind the first antenna. In AncTiistrotos it 



/ 



Fig. 41.— Mouth-parts of female t^enl^canthus .vlbidus. an", second antennae; la, labium; md, 

 mandible; 771. ft., maxillary hook; tbi', first maxilla; mx", second maxilla; Twip, maxtllipeds. 



is long and two-jointed, in Irodes and Txniacanthus it has but a single 

 joint, and in Phagus it is apparently wanting. First maxilla in the 

 form of a knob armed with from two to four plumose setse. Basal 

 joints of the second maxillae fused to the ventral surface, terminal 

 joints slender and bipartite or simple in the different genera. Max- 

 illipeds in their normal position but very rudimentary, the basal 

 joint fused with the ventral surface close behind the other mouth- 

 parts, and directed diagonally inwards and forwards. The terminal 

 joint consists of a slender and weak claw bent in a simple curve 

 {Txniacanthus, AncTiistrotos), or of two or more slender setse {Phagus, 

 Irodes). 



