of FormicidcR from Neio Zealand. 491 



is similar in some degree, yet, as in Cerotobosis, all the 

 discoidal cells are wanting, and the structure of the an- 

 tennas so very different, their distinction is definite. Strit- 

 migenys is separated from the foregoing by having only 

 six joints in the antennre of the female and worker ; the 

 winged female not known. Orectognathus has 5-jointi3d 

 antennae, the male is not known ; the female has not been 

 taken in a winded state. 



Genus Orectognathus, Smith. 



Head heart-shaped, deeply emarginate behind; man- 

 dibles porrect, bifurcate at their apex, near to which is a 

 sharp tooth or spine ; eyes lateral, of moderate size, and 

 composed of a number of circulai', convex, separated facets; 

 antennas inserted fonvards on the head, being 5-jointed in 

 the workers and females. Thorax oblong, much narrower 

 than the head, widest anteriorly, and with a short, acute 

 tooth at the margins of the prothorax ; the mesothorax 

 has also a small lateral tooth ; the metathorax with two 

 acute spines ; legs simple. Abdomen ovate and binodose ; 

 the first node petiolated and clavate, the second globose. 



Orectognathus perjylexus. 



Female. — Length 1| line. Pale ferruginous, the head 

 closely and finely punctured ; antennas and mandibles paler 

 than the head. Thorax shorter and narrower than the 

 head ; the prothorax rounded in fi-ont ; the scutellum with 

 the hinder margin rounded, somewhat projecting over 

 the metathorax, which is armed Avith two compressed, 

 acute spines ; the entire thorax closely and finely punc- 

 tured ; the legs paler than the thorax ; the anterior tibiae 

 with a spine at their apex, the intermediate and posterior 

 pair simple. Abdomen slightly ovate, nearly globose ; the 

 first node petiolated and rounded, the second semi-globose, 

 forming apparently the base of the abdomen. 



Worker. — The same size as the female, differing prin- 

 cipally in the form of the thorax, the anterior margin of 

 the prothorax being rounded ; the sides oblique, the upper 

 surface being kite-shaped and posteriorly truncate, the 

 angles of the truncation being armed with a spine ; closely 

 and finely punctured above ; the legs and abdomen as in 

 the female. 



Collected at Tairua, near Mercury Bay, by Captain 

 Brown. 



K K 2 



