106 bulletin: museum of comparative zoology. 



radial cell nearly attaining the wing-tip; recurrent nervure interstitial 

 with the first transverse cubitus; submedian cell of hind wing fully 

 half as long as the median. 



Platybracon Szepligeti. 



Dr. Mann obtained three species of this remarkable genus on Fula- 

 kora. Two species have already been described from the neighboring 

 islands; the type of P. depressus Szepligeti from New Guinea and since 

 recorded bv him from Aru; the second one P. insularis bv Cameron 

 from the Solomon Islands. Cameron's species appears to be repre- 

 sented in the collection by 16 specimens. I cannot be positive as 

 the original description is rather incomplete although it fits these 

 specimens so far as it goes. The other two are, I think, perfectly 

 distinct and undescribed. All, however, are very similar, including 

 the Papuan species. The following key will serve to distinguish them. 



1. Fourth abdominal segment with a distinct striate or rugose 



sculpture; antennae entirely black 2. 



Fourth abdominal segment smooth and shining'; antennae ferrugi- 

 nous apically 3. 



2. Fifth and following abdominal segments rugosely sculptured, the 

 anterior corners of the third and fourth segments rugose. 



P. depressus Szep. 

 Fifth and following segments smooth, anterior corners of third 

 and fourth segments smooth P. insularis Cam. 



3. Frontal projection below base of antennae small, in profile pro- 

 jecting only half as far forward as the mandibles; raised area of 

 1st abdominal segment three times as long as broad. 



P. debilis, sp. nov. 

 Frontal projection large, extending as far forward as the man- 

 dibles; raised portion of first segment a little over twice as long 

 as broad P. fortis, sp. nov. 



Platybracon insularis Cameron. 



Proc. Linn. soc. N. S. Wales, 1911, 36, p. 353. 



Sixteen specimens, all females, vary in length from 8.5 to 12 mm. 

 but are very uniform in sculpture and in the small size of the facial 



