new Species of Histeritlje. 251 



make this doubly certain, other specimens were sent to 

 Mr. F. Muir in Honolulu, m ho has examined them thoroughly ; 

 his results are given in the following note and drawings : — 



" The large Trypanaus thoracicus (marked (5* ) is a female ; 

 the speinuitheca is globular, large, and chitinized. I then 

 opened up the T. ensifer and Trypeticus marked ? , and 

 found them both to be males. 1 have therefore not opened 

 the specimens marked S- They are both of the Hister;d 

 type, but very feebly chitinized. Tryparujeus is much larger, 

 and the last abdominal segment (hidden beneath pygidium) 

 is simple, while in Trypeticus the last abdominal segment 

 is complex, with a pair of lateral struts and a large median 

 plate (all chitinized invaginations of the last segment and 

 not phallic). Cm 2 is very long in these two forms, and the 

 aedeagus can be drawn into the abdomen a long way, ami 

 one is apt to destroy it if one tries to only take off the last 

 segment of abdomen. 



"Trypeticus fay i (figs. 1 &2). — The last abdominal segment 

 lies under the pygidium, the lateral edges being extended 

 forward into the abdomen as two small struts {d) ; imme- 

 diately within the segment is the usual 'cloaca/ with the 

 anal opening on the dorsal face, and the ventral aspect ex- 

 tending into the abdomen as the second connecting membrane 

 {cm 2) which connects the base of the aedeagus to the body- 

 wall. In this case this membrane is of great length and 

 allows the aedeagus to be withdrawn into or thrust out of the 

 abdomen to a great extent. From each side of the base of 

 the connecting membrane there is a long, thin, chitinized 

 strut running forward into the abdomen ; from the ventral 

 edge of the ' cloaca,' between these two struts, there are two 

 thin semi-membranous })lates : the upper one (c) is some- 

 what spindle-shaped in outline, and slightly more chitinized 

 along the margin than in the middle ; the ventral one is 

 angular (6), and also more chitinized on the margin than in 

 the middle. The two plates and the lateral struts have 

 similar origin, viz. by the invagination of the base of the 

 second connecting membrane ; a section through the struts 

 near their base shows them to be hollow, with chitinized 

 walls, and the plates consist of two membranes closely applied 

 together. The lateral lobes are long and slender, semi- 

 chitinized except at the tips, the chitinization extending a 

 little way down the cylindrical basal piece. The median 

 lobe is long, slender, and cylindrical, and very slightly chiti- 

 nized, with the median orifice at the apex. The basal piece 

 is about one and a half times the length of the lateral lobes. 



