76 



NOTES ON GOREID.E AND NEIDID^E 



By K. Itergrotli 



I. THE GENUS MERCENNUS Dist. 



Of both sexes of this genus Distant has published a good descrip- 

 tion, but the sign $ before the first part of the description is a 

 misprint and ought to be ^f, and he says nothing abouth the 

 extremely remarkable structure of the female abdomen. 



The gênera of the group a. — b. of Stàl's subfamily Coreina wera 

 divided by Stâl in two Divisions, Mictaria and Amorbaria, a divi- 

 sion founded mainly on the structure of the sixth female ventral 

 segment, which in the Mictaria is arcuately sinuate behind with 

 right fissurai angles, whereas in the Amorbaria it is angulately 

 sinuate with the fissurai angles obtuse. I think with Distant that 

 there can be no doubt that Mercennus belongs to Stâl's group 

 a. — b., but in the structure of the fifth and sixth female ventral 

 segments it is widely différent from the Mictaria and Amorbaria 

 and quite unlike anything previously known in the whole family 

 Coreidœ. In the Mictaria -f- Amorbaria the apical margin of the 

 fifth segment is, as in the other Coreidœ, straight, and the sixth 

 segment is retracted in the middle, the apical margin being deeply 

 and broadly sinuate with the fissurai angles angulate and the cha- 

 racteristic basai fold (plica) entirely free and visible. In Mercennus 

 the whole apical margin of the fifth segment is broadly angularly 

 produced and has in the middle an incrassated triangular backwardly 

 directed process, the segment being much longer in the middle than 

 at the sides ; the apical margin of the sixth segment is straight, 

 slightly sinuate only at the sides near the apical angles, with the 

 fissurai angles broadly rounded, not at ail angulated, and with the 

 basai fold of the segment entirely covered by the apical process of 

 the fifth segment. Whether the basai plica is angular, as in most 

 Mictaria, or not, is impossible to know without dissection of a spé- 

 cimen, and I cannot sacrifice my only female spécimen for this pur- 

 pose. Even if the fold should prove to be straight, or sinuate, or 

 absent, Mercennus cannot be placed in Stâl's division aa on account 

 of the short rostrum and the head which is not produced before the 

 antenniferous tubercles. In the maie sex it differs from the Mictaria 

 in having the apical angles of the sixth abdominal segment shortly 

 but acutely prominent. I propose for this genus the Division. 



