Mr. J. O. Westwood on the Chigoe. 
199 
XL. On the Characters of the Chigoe or Jigger. Bg J. O. 
Westwood, F.L.S. <fc. 
[Read 1st May, 1837.] 
Mr. Sells having been so kind as to place in my hands the spe- 
cimens of the jigger which he had received in spirits from Jamaica, 
I have been enabled to make a minute investigation of several of 
its characters, with the view of clearing up some of the points 
concerning its structure and economy, which still remain subjects 
of doubt. 
Much uncertainty has prevailed relative to the tribe of insects 
to which the jigger belongs. Linnaeus named it Pulex penetrans, 
but with these observations — “ An Catesbaei Pulex, Bi'ownii Aca- 
rus, Rolandri Pediculus ricinoides vere specie differant ? an Acct- 
rus, Pcdicidus, Pulexl Catesbaeus suura delineat cum furca Podurce. 
Brown sui adscribit pedes octo Acari. Rolander vero pedes tan- 
tum sex Pulicis saltatorios, ut in vero pul ice, sed Phalangium can- 
croides nostras etiam corpus eodem modo intrat et dolorificum 
inhabitat ; dijudicent itaque Americani cujus sit generis et utrum 
una aut plures species.” — Syst. Nat. ii. p. 10 22. Latreille, also, 
in his Histone Naturelle, regarded it as belonging to the genus 
Acarus (vol. vii. p. 390). And see also Oken in his Lehrbuch der 
Naturgeschichte, Jena, 1815, vol. iii. p. 402. 
From the description and figure given by Swartz in the Trans- 
actions of the Royal Academy of Stockholm (Band ix. p. 40, pi. 
23, f. 10) ; Kirby and Spence, vol. 4, pi. xxiii. f. 10, (which figure 
represents the abdomen of the insect of the ordinary size, and 
with the anus bifid) ; Dumeril, Considerations Generates sur les In- 
sectes, pi. 53, f. 4, (which represents the insect with the abdomen 
of the ordinary size, but terminated by an elongated, slender, 
forked appendage like that of a Podura, and fig. 5, which repre- 
sents the female with the large distended abdomen) ; and still more 
recently from the work of Pohl and Kollar ( Brasiliens vorzuglich 
Idstige Insecten, fig. 5) ; it is evident that the jigger belongs to the 
same tribe as the flea, and that there are two species of Acaridee 
( Ixodes Americanus and I. crenatus), which are also obnoxious in 
tropical America. 
The great length of the rostrum how T ever, (which Linnaeus cor- 
rectly described as being “ longitudine corporis,”) together with 
the diversity in the habits of the insect, induced Latreille to ob- 
serve that it “ forme prohablement un genre particulier,” ( Regne 
Animal, 2d edit. vol. v. p. 351) ; and the late Rev. L. G lidding, 
Q 
VOL. II. 
