NO. lO 



MORPHOLOGY OF GNATHOTRICHUS — SCHEDL 



45 



THE SPIRACLES 



Corresponding to the number of the epipleurites, there are eight 

 spiracles in the male and seven in the female. These are implanted 

 in the membranous epipleurites and the apical epipleuro-tergite re- 

 spectively. The eighth pair of spiracles in the male are always rudi- 

 mentary. Gn. materiarhis Fitch shows comparatively the best de- 

 velopment in this regard. The seventh epipleurotergite of the female 

 bears a pair of spiracles which are well developed and only very 

 slightly smaller than the others. There also occurs one pair of spiracles 

 on the prothorax. They lie under the produced caudad-lateral angles 

 of the pronotum. 



Fig. 24.- 



-Spiculum ventrale in female : A, Gnathotrichns sulcatns Lee, 

 B, Gnathotrichns materiarhis Fitch. 



Br, brachium; Ca, caput; Com, commisura. 



THE LEGS 



The three pairs of legs are illustrated in figures 25 and 26, They 

 do not vary strikingly from species to species neither in form nor in 

 sculpture. Therefore the drawings were made from Gnathotrichns 

 materiwius only. Tlie legs present all the typical segments common 

 in Coleoptera, which are the coxa, the trochantin, the femur, the tibia, 

 the tarsus and the pretarsus. 



Coxa. — The coxa (fig. 25) differs considerably in shape in the three 

 pairs of legs. The coxa of the prothorax (A) is very stout, ball-like, 

 the mesocoxa (B) is slightly longer and the metacoxa (C) is nearly 

 twice as long as the forecoxa. The proximal end of the fore- and 

 mesocoxa show distinct indications of a basicostal suture (a). In the 

 fore-coxa the basicostal suture is formed into an external ridge 

 ventrally, which becomes lower and indistinct laterally. In the meso- 

 coxa a simple suture (a) indicates the limitation of the basicosta. The 

 basicostal area of the forecoxa (Be) is about twice as long as the 

 same structure in the mesocoxa. The basicoxite (Bex) is present as 



