ARPACTICUS. 



213 



The thorax consists of four, the abdomen of six seg- 

 ments, the terminating one giving issue to two long, linear, 

 finely-serrated setae, fully the length of the body. The 

 upper or cephalo-thoracic segment, comprising the head, 

 consolidated with it, is beaked, ha\ing a short conical 

 elongation in the centre. 



The antennae (f. 3 ) are short, of about ten articula- 

 tions in the female, and at the junction of the fourth with 

 the fifth there is a small lateral joint in both sexes. At 

 the fifth ling, in the male, is situated the swelling and 

 hinge-joint. The antennules (f. 3 b) consist of two arti- 

 culations, the first having a shoot sent off from about its 

 centre, divided into two joints, which are furnished with 

 several hairs ; the second being terminated by five setse, 

 the three internal of which are the longest, and have a 

 joint near the middle of their length. 



The mandibles (f. 3 c) resemble very much these organs 

 in the Canthocamptns minutus, the teeth, however, being 

 more distinctly seen. The posterior foot -jaws (f. 3 e) are 

 composed of three articulations, the first being long, the 

 second short and curved, and the third forming a strong 

 curved hook, the two terminal combined having the ap- 

 pearance of a strong claw. 



The first pair of feet (f. 3/) consists of two unequal 

 stalks, arising from a common base of considerable length. 

 The superior is the longer of the two, and is composed of 

 two nearly equal stalks, serrated on their upper edge, the 

 second terminating in three short hooks. The inferior 

 stalk is also formed of two articulations, the first of which 

 is much the longer of the two, and is serrated, the second 

 being very short, and terminating in two curved hooks. 

 The three other pairs of feet (f. 3 g) consist, each stalk, of 

 three articulations, furnished with long hairs, one or two 

 of the long terminating ones being finely serrated. The 

 external stalk is larger and longer than the internal. All 

 three pairs of feet resemble each other. 



The supports or fulcra (f. 3 d] are composed each of a 



