oGO ON TFIE STRUCTURE OF THE ANTENN/E 



the observation : " The cavity behind the eye, which appears 

 to be partly closed by a small lobe that may be distinctly seen 

 to rise and fall, I am disposed to believe is an organ of respira- 

 tion rather than the analogue of the antennae, as suspected by 

 my friend, Mons. Latreille ; and the absence of spiraculae down 

 the sides of the abdomen strengthens my opinion. Little as 

 we know of the uses of the antennae beyond the sense of 

 touch, it is impossible to say that the maxillary palpi may not 

 perform in this order the office of antennee, and that the orifice 

 behind the eye may not be also adapted to hearing." 



Subsequently, however, Mr. Curtis obtained sj^ecimens of 

 P, Hirnndinis, in which the antennae " are as long as the 

 head, placed above the eyes, and received when at rest into a 

 deep groove, and when erected look like the ears of a rabbit. 

 They are four-jointed, and the basal joint has a few long 

 bristles." 



In the summer of 1831, I had occasion to investigate the 

 structure of this order, and gave much attention to this portion 

 of ^the subject; and, after considerable trouble, succeeded in 

 extracting the antennae of several specimens of P. Canis from 

 their cavity behind the eyes. In this species these organs are 

 broad and four-jointed; the first joint is short; the second 

 larger, and somewhat cup-shaped, and produced on the outside 

 with numerous rigid setae at the external angle, forming a 

 defence to the terminal joint, which is large, ovate, or rounded, 

 and subdepressed with numerous denticulations on the outer 

 edge ; the third joint is short and narrow, forming the base of 

 the fourth joint. 



In the 417th plate of Mr. Curtis's British Entomology for 

 August 1832, another species of flea was illustrated under the 

 name of CeratoplujUiis elongatiis, with the observations, that, 

 from repeated examinations, that gentleman had found it neces- 

 sary to divide the Pulices into two genera; that the P. Talpcc, 

 previously figured as an example of the genus Pulex, belonged 

 in fact to the new genus ; and that the discovery of the antennae 

 of P. canis, by Mr. Haliday, rendered it necessary to erase 

 the paragraph in the 114th folio, quoted above. A copy of 

 Mr. Haliday's figure of the antennae of the latter species (which 

 is considered as a true Pulex) is introduced into Mr. Curtis's 

 plate of Ceratojiliyllus ; but it is not quite correct, being de- 

 scribed as only two-jointed, the basal joint having only a single 



