234 THE ENTOMOLOGIST. 



ON THE MORPHOLOGY AND CLASSIFICATION OF THE 

 AUCHENORRHYNCHOUS HOMOPTERA. 



By Dr. H. J. Hansen. 



(Continued from p. 217.) 



The first pair of spiracles lies, as in the Cercopidae, on the 

 under side, a little within the lateral margin close to the posterior 

 margin of the metasternum ; the second pair lies at the antero- 

 exterior angle of the second segment near the lateral margins, 

 so that they are looking laterally and upwards. The third and 

 eighth pairs of spiracles lie in the outer solid Pleural Plates, 

 the fourth to seventh pairs in the anterior part of the narrow 

 Plates in the inner part of the Pleuron. All the spiracles are 

 small. 



In the Membracinae the abdomen, as is well known, is often 

 elevated very considerably, compressed, and strongly chitinized, 

 therewith following certain peculiarities in structure, and in the 

 situation of the spiracles. As an example, the structure in 

 Centrotns cornutus is now described. In this the tergite of the 

 first segment is moderately feeble, somewhat peculiarly formed, 

 and terminates a good way from the lateral margin ; the sternite 

 is longer and more solid than in Tettigonia, and is not interrupted 

 medianly. The second segment's tergite is tolerably feeble and 

 short, ends a good way from the lateral margin, and at its ends 

 a small pleural plate is found. On both segments there is thus 

 a somewhat large space between the lateral margins of the tergite 

 and the sternite. As regards the second segment, the third seg- 

 ment's pleural plate and the lateral part of its tergite form 

 together a strong solidly chitinized wedge, which fills up the space 

 mentioned. On the third segment's tergite one sees at the anterior 

 margin a deep transverse furrow, and in front of this an arched 

 part, which one would readily take for the posterior part of the 

 tergite of the second segment— which it is not — as this is situated 

 in advance thereof as a more feeble short stripe. On the third 

 to eighth segments the inner part of the Pleuron is only a some- 

 what narrow membrane, while its chitinized outer plate is very 

 considerable. The first and second pairs of spiracles are con- 

 sequent upon the peculiar structure and altered bodily form of 

 the first segment, transferred considerably above the lateral mar- 

 gins, and look backwards ; the second pair lie in the tiny pleural 

 plate a little higher up than the first pair ; the third to eighth 

 pairs are transferred to the intero-anterior angles of the pleural 

 plate. 



In Memhracis tectigera somewhat comparable circumstances 

 are found, but here the pleural plates of the third to eighth seg- 

 ments are separated from the tergite and sternite only by a 



