200 
Mr. J. O. Westwood on the 
in his unpublished MSS., accordingly raised this insect to the rank 
of a distinct genus, under the name of Sarcopliaga penetrans. 
From all the accounts published of the habits of this insect, it 
is evident that its natural and ordinary locality is hot and sandy 
ground, (indeed Fold and Kollar call it the “ Sandfloh”) ; and that 
on extracting the jiggers from the human foot, they are found in 
no other state than that of having the abdomen immensely swollen, 
and filled with eggs, like the gravid queen of the Termites. Thus 
females only burrow into the feet ; and Messrs. Fold and Kollar 
observe, that the front part of the body is turned inwards, whilst 
the anus is placed at the spot where the jigger entered into the 
flesh. Hence they suppose that it is only for the purpose of find- 
ing a more abundant nourishment for the developement of their 
eggs, that they burrow into the feet, adding, that “ as, besides, no 
larvae or maggots were found in the feet, but tolerably forward 
eggs at the orifice of the anus, it is probable that the female lays 
its eggs on the ground, where they transform themselves into larvae, 
pupae and perfect insects.” 
But this opinion seems to me to be completely disproved by 
the fact, that if the jigger be left to itself the most serious conse- 
quences follow, which must, I apprehend, be caused, not by the 
continued operations of the female (although from the immense num- 
ber of her eggs, and the great diversity of size between those near 
the orifice and those at the other end of the egg-ducts, it is evident 
that a considerable time must be occupied in the deposition of the 
eggs), but by the workings of the young when hatched ; and this 
is further confirmed by the fact, that similar ill effects ensue when 
the jigger is not extracted entire, some of the embryos remaining 
in the wound. The observations also of M. Defrance, published 
in the Encyclopedic Methodique, vol. x., upon the habits of the 
larvae of the common Palex irritans, also favour my view of the 
subject. 
In like manner I cannot adopt the opinion of Dr. Rodschied 
(cited by Fold and Kollar, from his work upon the Essequibo 
district), that the jigger lays no eggs, but that the larvae are de- 
veloped in the abdomen of the mother, and are there even trans- 
formed to pupae. This, he says, can be distinctly observed if a sand- 
flea be extracted, which has nestled for some days ; its abdomen 
lias then increased to the size of a pea, and one can clearly see 
the thorax as well as the proboscis and eyes. These little bodies, 
he adds, found thus swollen, may rather be taken for pupae than 
for eggs, for they are too large to be the latter. He further 
thinks that the female of the sand-flea feeds, by suction, the larva 
