80 
THE CABINET OF NATURAL HISTORY 
it be disturbed, penetrates deeper, and produces an ulcer 
which frequently becomes fatal.” 
We are informed that Killock, previous to this attack, 
while at work, usually wore his shirt-sleeves rolled up 
above his elbows; and that, while in George Town, Deme- 
rara, he generally slept on deck. It is easy then to sup- 
pose, that the CEstrus, or parent fly, had availed itself of a 
proper opportunity to deposite its egg upon his arm, proba- 
bly by a slight puncture of the skin, by means of the ovi- 
positor with which it is furnished. When the larva had 
attained its full size, it dropped out, instinctively searching 
for a covering of natural earth, in which to undergo the 
intermediate state of pupa, which it is destined to assume 
for a time before it becomes a winged insect. The instinct 
of the parent, however admirable under ordinary circum- 
stances, was, of course, insufficient to provide against the 
accident of Killock’s being a seafaring man, — and the larva 
could not have attained the perfect state, for want of the 
proper nidus in which the pupa is accustomed to repose. 
Had a flower-pot, containing earth, been on board the ves- 
sel, the different changes of the insect might have been 
observed, and our knowledge of the species completed. As 
it is, we are acquainted with the larva alone. Its descrip- 
tion is as follows: — 
Length, in its present shrivelled condition, seven-tenths 
of an inch; circumference round the centre, or thickest 
part, one inch; colour pale dingy apple-green, tinged with 
brown. The mouth appears to have been somewhat tubu- 
lar, but is furnished on its upper part with a pair of sharp, 
minute, hooked crotchets, of a shining black colour, pro- 
bably for the purpose of adhering more firmly to the spot 
from which it was desirous to draw its food. The eyes 
are large and prominent; their colour brown. The body is 
composed of nine rings or segments, exclusive of the head 
and anal portion. There are thus, in all, eleven segments, 
besides the mouth, the exact number of which the larvse of 
the European species consist. There are no feet. These 
organs are, however, obviously supplied by transverse cir- 
cles of small black spines or hooks, with which the princi- 
pal segments of the body are furnished; and, besides these, 
there are several rounded unequal protuberances on the back 
and sides. The latter are possibly produced or rendered 
more apparent, by the decrease of size which has taken 
place. Supposing these minute spinous hooks to be, along 
with the skin, under the control of muscular action, (and 
Lyonnet has beautifully exhibited the complicated muscular 
structure of another larva,) then, according to the direction 
in which the hooks are pointed, a wriggling motion would 
produce either outward or inward progression, and serve 
all the purposes of locomotive organs, just as (to use a 
familiar illustration) an ear of barley placed within the 
sleeve of a pedestrian, works its way in a direction oppo- 
site to that to which its beard is directed. 
As further testimony to the above, the following is copied 
from the Journal of the Academy of Natural Sciences of 
Philadelphia, being an extract of a letter from a gentleman 
from whose leg this larva was extracted. 
“After a very sultry day’s march, and being very much 
fatigued, I went to bathe in the Chama, a small stream 
emptying in the lagoon of Maracaibo. Not long after 
coming out of the water, I received a sting from some insect, 
in the left leg, over the upper and forepart of the tibia; it 
was several days attended with a considerable degree of 
itching, but without any pain, and I continued on my 
journey some few days longer, without experiencing much 
inconvenience, except during several periods of perhaps 
two or three minutes continuance, when an acute pain came 
on suddenly, and was severe whilst it continued, and then 
as suddenly subsided. On my arrival and during my con- 
tinuance at II Rosario de Cucuta, I walked with difficulty; 
there was a considerable tumefaction over the tibia, which 
had the appearance of an ordinary bile, (Phlegmon) in the 
centre there was a small black speck; the usual applications 
were used without any success, and the tumour became 
more irritated and inflamed, and thus it remained for some 
days, attended at times with a most acute pain, which, for 
a few minutes was almost intolerable. 
“In returning to Maracaibo, I had to descend the Cotta- 
tumba in an open boat, without any shelter, and being wet 
to the skin by the cold rains which fell every night, I suf- 
fered much, and was almost constantly tormented by the 
tumour, which became more painful at those particular pe- 
riods than usual; during this passage, which lasted for twelve 
days, I was induced to scarify it, and had recourse to the 
usual topical applications, but without success. At times I 
imagined that I felt something moving, and suspected that 
there was something alive beneath the skin. 
u After my return to Maracaibo I became scarcely able 
to walk, and was in a manner confined to my quarters. In 
this situation I continued two weeks longer, the tumour 
having began to discharge, and without any diminution of 
the painful periods. 
“ Being now nearly worried out, it occurred to me to 
try a poultice of tobacco, which was used for several nights, 
having previously scarified the tumour; during the day, I 
frequently dusted it with ashes of segars: as an ingredient, 
I used rum instead of water, in making the poultice. On 
the fourth morning after this remedy, I felt considerable 
relief, and on the fifth, with a forceps, I drew out the worm 
which you have now in your possession, and which was 
then dead. 
