APHANIPTERA. — PULICIDZ. 4.9 
Talpz, Musculi, and Vespertilionis. The largest. British species is 
found upon the mole, Ceratopsyllus Talpze Curt. The largest species I 
have seen has been sent to me by Mr. R. H. Lewis, with the name of 
Pulex Echidne, that gentleman having captured it in Van Diemen’s 
Land on Echidna Hystrix, or the Australian porcupine.  P. gigas 
Kirby (Faun. Bor. Amer. p. 318. pl. 17. f. 9.) is two lines long, but it 
is not known upon what American animal it was found. 
In warm and more especially in tropical countries, these insects are 
exceedingly troublesome; but in the West Indies and South America 
there is an insect belonging to the family having habits different to 
those of the common flea, which is even still more obnoxious; this 
is the Chigoe or Jigger, Pulex penetrans Linn.*, an insect of very 
small size, which lives in the open country, and during the dry 
season incredibly multiplies in sandy and dusty places. It chiefly 
attacks the naked feet, both of men and dogs +, particularly between 
the toes and nails, burying itself deep into the skin, and occasioning 
by its constant irritation the most violent indisposition, inflammation, 
swellings, ulcers, and even death. After one of these insects has 
effected a lodgement in the skin, its body becomes enormously dis- 
tended, acquiring the size of a pea (jig. 123. 17. seen in front; 18. 
ditto magnified, seen sideways) ; the head, thorax, and legs retaining 
their ordinary size, the abdomen alone becoming swollen and filled 
with an immense number of eggs; in this state the greatest care 
is requisite in extracting the mass entire. The specimens which 
thus burrow into the flesh are certainly impregnated females. No 
author has noticed the discovery of larve or pupe in the feet 
or elsewhere ; hence Pohl and Kollar (Brasil. vorzugl. list. Ins. 
tab. annex. fig. 5., translated in Mag. Nat. Hist. vol. ix. p. 294.) 
* Long regarded as an Acarus; it was first proved to be a flea by Olaus Swartz. 
Guérin (Icon. R. An. Ins. pl. &. f. 9.), Dumeril ( Consid. Génér. pl. 53.), and Pohl 
and Kollar have given figures of this insect. The two former figure, also, indi- 
viduals with the abdomen of the ordinary size, terminated by a slender appendage, 
forked at the tip. Is this the male? Kirby and Spence (Jntrod. pl. 23. f. 10.), 
and Pohl and Kollar, have represented it without this appendage. Is this the un- 
impregnated female? M. Guérin has also figured (Jeon. R. An. Ins. 2. fig. 9. a) a 
specimen of*P. penetrans with the long anal appendage, which he doubtingly 
describes (in the description of the plates of the Jconographie, of which he has been 
so kind as to send me proof sheets) as the male organs of generation; the un- 
impregnated female not possessing this appendage, which, from the habits of the 
insect, cannot be an ovipositor. 
+ According to Pohl and Kollar (p. 10.), the Bicho do Cachorro, or dog chigoe, 
is a distinct species from the Bicho de pé, or P. penetrans. 
