216 THE ENTOMOLOGIST. 



Cicada, posterior to the eight s'piracle-hearing abdominal segments ^ 

 three distinct segments in addition to the " anal flap" (= telson), 

 and that the ninth and tenth abdominal segments are, in the 

 male, extremely modified ; whilst in the female only the ninth 

 is very strongly modified, the tenth being small and only slightly 

 altered.) 



The first pair of abdominal spiracles lies on the ventral side of 

 the body close to the lateral margins in a depression at the base 

 of the abdomen, surrounded by solid chitin (a part of the meta- 

 sternum), which, particularly in the male, is very thick, and of 

 a considerable breadth ; they are transverse like the thoracic 

 spiracles, but somewhat shorter than these. In most females' 

 they are generally not diificult to see when the abdomen is bent 

 a little upwards, but in some females, and in most males, they 

 are covered by the so-called "Opercula." The seven remaining 

 pairs of spiracles are considerably smaller than the first pair, 

 and of different structure ; they are entirely open, loith an oval or 

 almost circular orifice, the Peritreme being a solid ring, which is 

 also furnished with a great number of hairs directed towards the 

 centre of the spiracle. The locking-mechanism lies a little behind 

 the Peritreme. The first of them (thus the second pair of abdo- 

 minal spiracles) is not altogether easy to discover. Tliey lie like 

 the first pair on the under side of the abdomen a little from the 

 lateral margin close to the front margin of the second abdominal 

 segment, but the chitin of this segment is inclined inwards 

 (downwards seen from below) in such a manner that a transverse 

 furrow arises, so that the spiracles actually lie near the bottom 

 of the outer angle of this furrow, looking forwards and towards 

 the insect's middle plane. In the female one can see them with- 

 out preparation, but in the male they are often concealed by the 

 "Opercula." Each of the third to eighth abdominal spiracles 

 lies in the sternite itself a little behind its front margin, and 

 close to the Pleuron. 



2. Cercojjidcs. — The first tergite extends right to the lateral 

 margins, where it is moderately long,* but not strongly chitinized; 

 towards the median line it shortens strongly, or even disappears 

 as a solid formation ; the sternite is short, well chitinized at the 

 middle, and terminates far from the lateral margins. The second 

 tergite is somewhat long, well chitinized, and extends right out 

 to the side margins ; the sternite is shorter medianly than the 

 tergite, and is still shorter towards the lateral margins ; it extends 

 right out to this, and almost to the apical margin of the tergite 



-■= In the original the word is " broad," but Dr. Hansen now accords with 

 me that the words " broad," " narrow," " long," " short " should refer solely 

 to the situation of the margin in question with regard to the longitudinal 

 axis of the insect. This paper therefore is not a literal translation of the 

 original in these respects, but represents Dr. Hansen's present views. — 

 G. W. K. 



