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 (Estrus, or parent fly, had availed itself of a 

 proper opportunity to deposit its egg upon his arm, proba- 

 bly by a slight puncture of the skin, by means of the ovi- 

 positor with whicli 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 iiefore 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 diflerent 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. Tiie 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 larvae 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 h':oks 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 heard 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 verj' 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 da3's 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 xny con- 

 tinuance at II Rosario de Cucuta, I walked with difliculty; 

 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 witliout 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. 



" 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. 



