34. 



R A R 1) W J C K E' 8 S C ! F K C E - G O S 8 1 P. 



hooks. An old Indian of Ega showed me the most 

 effective way of proceeding, which was to stupefy 

 the grub with strong tobacco-juice, causing it to 

 relax its grip in tiie interior, aud then pull it out of 

 the narrow orifice of the tumour by main force." 

 ("The Naturalist on the Amazons.") 



Alexander von Humboldt had already published 

 an account of a fly witli similar habits, which he 

 named CEdrus Jiomiiiis. According to his observa- 

 tions, the larvse of the insect are not rare on the 

 arms, back, and abdomen of the natives, within 

 large tumours, at the top of which is a minute 

 orifice, through which the grub communicates with 

 the outer air. At a fitting period the larva forces 

 its way through this hole, falls to the earth, and 

 there undergoes its final changes. 



All this is piecisely what occurs in the case of 

 the European gadflies. Every resident in the 

 country must have noticed lumps or swellings on 

 the backs of oxen, especially of heifers, which are 

 called by the rusticswhorbles (fig. 27) or wormuls, no 

 doubt meaning worm-holes. Within each of these 

 swellings lies ensconced a grub, the produce of a 

 large brownish fly, which was named by Bracy 

 Clark Ilypoderma bovis (fig. 28). From August to May 

 the head of the little creature is plunged in a mass of 

 purulent matter, on which it feeds, while the tail, 

 in which the breathing apparatus is situated, is 

 thrust through a minute hole at the apex, in order to 

 come in contact with the outer air. During the 

 month of May the larva manages to enlarge the 

 orifice, through which it drops to the ground and 

 seeks a convenient place of shelter.* 



This little bit of life-history points to a close 

 analogy between our gadfly and the human parasite 

 of South America. Moreover, a connecting link is 

 found in a narrative given us by Don Ramon Paez 

 in his "Life in the Llanos of Venezuela," wherein 

 he writes: "Agapito, our host, had an easy time 

 as overseer of this domain, his only occupation 

 being from time to time to scour the savannah in 

 search of young foals which might have been at- 

 tacked by the 'gusano.' This is the larva of a 

 species of fly deposited in the umbilical cord of the 

 new-born foal, and which, if not promptly remcved, 

 will eat into their very vitals." 



It will not escape observation that the horse-fly 

 of Venezuela aud the human parasite of the neigh- 

 bouring state of New Granada both pass by the 

 name of Gusano. 



On the whole, wc can scarcely avoid the conclu- 

 sion that some species of ox-fly not unfrequently 

 leaves its proper pasture-ground, and deposits ils 



* No great harm follows from the attacks of tlie gadfly to 

 our herds; but we are told by Dr. Bernard Altum, in his 

 lately published work, '• Forst-Zoologie Saugethiere,'' that in 

 Germany the hides of the wdd deer are often so riddled by 

 these srubs as t ) render them unfit for the purposes oi the 

 tanner. 



eggs on the human frame. Certainly Van der 

 Hoeven ("Handbook of Zoology," i. ) is inclined to 

 think that the injury is due to this cause, or else to 

 some species of Tachiiia. 



Other authorities, however, introduce us to a fly 

 whose mode of action bespeaks it a place among 

 the flesh-flies, — a group very far removed from the 

 gadflies. 



One species infests the valleys of Mexico, both 

 North and South, though not found on the high 

 table-lands. This fly lays its eggs in the nostrils of 

 human beings ; the larvfe are quickly hatched ; and 

 then follow rapidly ulceration, erysipelas, and 

 meningitis. The insect gradually eats its way into 

 the mouth, eyeballs, cheeks, &c., until in a fortnight 

 or three weeks the miserable victim succumbs to 

 his fate, ("Archives medicales Beiges," 1867.) 

 The same or a similar plague is not uncommon 

 farther south. Captain Burton does not appear to 

 have been himself cognisant of any case in Brazil, 

 but he speaks of hearing "many tales told of 

 negroes losing their lives in consequence of the 

 grub being deposited in the nose and other places." 

 ("Highlands of the Brazils,") A more detailed 

 account I translate from M. Girard's work, "Les 

 Metamorphoses des Insectes," published in 1867, 

 " Since the transportation of prisoners condemned 

 to hard labour to Cayenne has been in vogue, 

 several fatal cases have been traced to the opera- 

 tion of a fly named by Dr. Coquerel Lucilia homini- 

 vorax (fig. 31). Other convicts have escaped with the 

 loss of their nose ; for it is into the nose and cheeks 

 of sleepingmen, especially whenin a condition of help- 

 less intoxication, that the insect introduces its eggs. 

 The maggot, which is furnished with strong hooked 

 mandibles, establishes i'self in the interior of the 

 nostrils, and in the frontal sinus ; from thence it 

 passes to the eyeballs, and causes gangrenous 

 wounds in the eyelids; or it enters the mouth, and 

 gnaws away the gums, the palate, and the pharjTix, 

 causing intense anguish. The patient experiences 

 at first an itching sensation in the nostrils, accom- 

 panied by severe headache and swelling of the nose, 

 which is soon followed by ulceration of the parts 

 <'i{fected, during which the larvai force their way 

 through the skin, and make their appearance on 

 the surface. As tiie evil advances, violent inflam- 

 matory action sets in, with all the symptoms of 

 meningitis and erysipelas, until death releases the 

 victim. The grub in question is known in Cayenne 

 as the ver macaque, and was published to the world 

 so long ago as 1735 by M. Arturc, physician to the 

 king of Cayenne. It is probable that the ver 

 motjacull of Mexico, which attacks men and dogs, is 

 an analogous species. 



"Dr. Coquerel has a^so made known another fly 

 under the name of Idia bigoti, indigenous in Senegal, 

 which stings the soldiers on duty near the coast. 

 In all likelihood this stinging is the introduction of 



