THE AUCHENORRHYNCHOUS HOMOPTERA. 117 



rather thick at the base, and tapering to the apex ; it consists 

 (see pi. i. f. 1,* representing Cicada prumosa, Say) of Jive long, 

 mutually almost equally long, segments ; with a lens one can 

 easily perceive the two or three basal {alwaijs mutually long) 

 flagellum-segments, but in dried specimens the fifth is not always 

 distinguishable separately. 



On the under side of the first and second segments of the 

 fiagellum there is a very large number of sensory organs. Each of 

 these consists of a pit, from the bottom of which sticks up a 

 blunt S23ike ; these organs are of two somewhat different forms. 

 Some are considerable (fig. la, m), the pits being remarkably 

 wide in proportion to their depth ; the spikes are stout, and pro- 

 ject somewhat out from the pits. The others (tig. 1 a, n) are 

 much smaller, the pits being narrow and proportionately deep ; 

 the spikes are slender, and scarcely project beyond the orifices 

 of the pits. 



On the three last segments of the fiagellum I have found a few 

 of the smaller kind of these organs. 



v' 



"^2. CercopidcB. 



y/ I have microscopically examined the antennae of a Brazilian 



^^ MonecphorayTriecphora sanguinolenta}'^ Aphrophora alni, and 

 '^Philcenus spumarius, that is to say, representatives of the three 

 groups into which the Cercopidae were divided by Stal (' Hemi- 

 ptera africana,' iv. 5^). I have also examined with a strong 

 lens two examples ofMachcBrota (representing Stal's third group), 

 and a large number of examples belonging to various genera of 

 the first two groups. The antennae have a very close mutual 

 resemblance, both superficially and in their detailed structure, 

 while at the same time differing considering from the other 

 families. They are always placed in front of the eyes in pits on 

 the forehead close beneath the margin, which, at least just at 

 this place, projects freely, separating the vertex from the fore- 

 head. The second segment of the peduncle (pi. i. f. 2 and 3) is 

 subequal to the first, approximately cylindric, ivithout sensory 

 organs, its broad distal end being cup-shaped. The fiagellum 

 consists of a single, very thick basal segment, and an extremely fine 

 tolerably long bristle, which is not separated from the basal seg- 

 ment by any articulation in" Monecphora, while it is somewhat 

 indistinctly articulated in'- Aphrophora. The basal segment is 

 short and obliquely oviform (or almost spherical), its basal part 

 prolonged in a short thin stalk, by which it is fastened to the 

 concave part of the second segment of the peduncle. It has a 

 small number (from six to nine), near the apex on the one side, 

 of simple proportionately very large sensory pits, each with a 



'■- These references are to the plates in the original paper, which should 

 be compared with this translation. — G. W. K. 



KNTOM. — APRIL, 1900. L 



