THE AUCHENORRHYNCHOUS HOMOPTERA. 217 



(the sternites of these two segments are not visible without pre- 

 paration, and the posterior coxae should preferably be cut away, 

 as they project forwards over them, and partly cover them). The 

 third to eighth segments are formed essentially like those in the 

 Strididantia. Only the inner part of the Pleuron is always very 

 distinctly developed, but not, however, particularly broad ; it is 

 now and then almost entirely membranous, but occasionally con- 

 tains chitinous portions. In Ajjhrophora alni there are thus 

 found in the membranous part of the Pleuron of the third to 

 fifth segments two distinct narrow chitinous plates (an anterior 

 and a posterior) in each segment. 



The first pair of spiracles lies inside the lateral margins on 

 the lower side of the body as far forward as possible towards the 

 posterior margin of the metasternum, and on account of the shape 

 of this plate, the projection of the coxa and the aperture of the 

 spiracle being rather feebly defined, the spiracle is difficult to 

 perceive. The second pair of spiracles lies on the lateral margins 

 in a small chitinous piece, which projects a little forward and 

 downward from the lateral angles of the second sternite of the 

 abdomen, and, indeed, may appear to correspond with the large 

 outer pleural chitin-plate in the following segments. The third 

 to eighth pairs lie on the under side in the inner part of the 

 Pleuron, and if this contains chitinized fragments it is located 

 in the first of these. At least the second to eighth pairs of 

 spiracles are cleft-shaped, fairly large. 



3. Jassidce. — The structures of this family agree largely with 

 the foregoing. The form, the structure of which I have found 

 easiest to study — and, if one likes, most typically developed — 

 is the female of the very common Tettigonia viridis, L., for 

 which reason it is the basis for the following observations. 



The tergite of the first segment is not developed medianly, 

 but more towards the side it appears as a not particularly long 

 plate, which then contracts again, and terminates a little from 

 the lateral margin ; the sternite is very short, and does not 

 extend quite out to the lateral margins, and is interrupted 

 medianly. The second tergite is well developed, not particularly 

 long, and extends almost to the side margins ; the sternite is 

 medianly nearly as long as the tergite, and its shortened lateral 

 margins reach almost to the lateral margins of the body. The 

 third to eighth segments are very similar to those in the Cerco- 

 pids. On the fourth to seventh segments each Pleuron consists 

 of a broad, strongly chitinized, exterior piece, and an inner band, 

 which for its entire length contains a narrow chitinous plate ; in 

 the third and the eighth segments an inner plate of that kind is 

 not developed. 



(To be continued.) 



ENTOM. — AUGUST, 1902. 



