PACHYTERIA OCHRACEA. 169 



apical ventral segments. In the female specimen before me 

 the fifth ventral segment is provided with a small rounded 

 notch in the middle of the hind margin, just as in the 

 female of Pachyteria Evertsi Rits. 



The examination of the above specimen has given rise 

 to severe doubts as to the correctness of my identification 

 of the two specimens (males) from Elopura , North Borneo , 

 which I received two years ago from Mr. Oliver E. Janson 

 and which I considered to belong to the above species , 

 as they agreed perfectly well, in regard to the coloration 

 with Waterhouse's description , showing only the two fol- 

 lowing differences: in stead of the three apical joints of 

 the antennae the five apical ones were dusky, and the 

 underside of the prothorax was not bluish black with a 

 yellowish transverse stripe , but of a dark chocolate brown 

 colour, with the exception of the contracted front portion 

 which is black as is also the case with a curved streak 

 across the coxae which leaves, however, the coxae free. 

 But now I find some striking structural differences between 

 these two sexes : in the male the labrum is larger, less con- 

 vex , more closely punctured , and more deeply notched 

 anteriorly; the antennal joints are distinctly more elongate 

 and consequently the antennae are noticeable longer ; the 

 excavation of the head between the antennae is deeper and 

 the top of the antennary tubers more protruding. By far 

 more striking differences , however , exist in the shape and 

 sculpturing of the prothorax which in the male is deci- 

 dedly broader and larger than in the female : whilst in the 

 female the prothorax is densely rugose and opaque on the 

 disk, it is in the male but very densely punctured with 

 glossy interstices ; in the male the lateral spines are con- 

 siderably more elongate , and , last not least , the underside 

 of the prothorax , which is shining and transversely wrin- 

 kled in the female , has in the male its brown coloured 

 portion so densely punctured that it becomes opaque and 

 obtains a leathery appearance , and this portion is as dis- 

 tinctly defined as if it had been a piece let in. When the 



Notes from tlie Leyden Miuseum, Vol. XII. 



