(E S T R U S. 
41.7 
though tired ; and, as this rnoft frequently happens du¬ 
ring warm weather, it is in general attributed to mere 
lazinefs. Thefe fymptoms I have been a witinefs to feve- 
ral times, to the fevere chaftifement of the horfe and 
vexation of the rider: on the removal of the bott, the 
cure is inftantaneous. If this mode of removing them 
were generally complied with, but few could efcape, and 
their numbers would be very much reduced ; and thole 
who wifh to obtain them for cabinets of natural hiftory, 
or for examination, will alfo find this the moll effectual 
way. We know of no medicine that will detach them from 
the ftomach or inteftines, though there are not wanting 
abundance of infallible noftrums among the very nume¬ 
rous profeffors of this art. 
“Another both eafy and effe&ual mode, at lead: for 
the CE. equi, is to deftroy the eggs which are depofited 
on the hairs of the horfe, and are eafily feen and removed 
by a pair of fciflars, or by means of a bruffi and warm 
water. In the Iheep it will be much more difficult to pre¬ 
vent or deftroy them by any of thefe means ; particularly 
if they are feated in the maxillary finufes: in this cafe 
trepanning would be infufficient, as they would probably 
be concealed among the convolutions of the turbinated 
bones. Perhaps the removal of the fheep to a diftant 
pafture during the months of June and July, while great 
part of the botts are yet on the ground in the chryfalis 
ftate, and not bringing them on the pafture again till the 
letting-in of the winter, would be the means of deftroying 
them moll effectually; and, if repeated for two or three 
years fucceffively, when they are particularly troublefome, 
the farmers might eventually find their account in it.” 
Mr. Clark then proceeds to explain how far the pre¬ 
fence of thefe infeCts, or their larvae, may poffibly be of 
ufeto the horfe, Iheep, &c. but intofuch fanciful enquiries 
we do not enter, being well fatisfied with the valuable in¬ 
formation w'e have obtained ; and refer the more curious 
reader to the third vol. of the Linn. Tranf. We lhall 
now briefly notice the remaining fpecies. 
6. CEftrus cuniculi: black; wings brown ; thorax 
black as far as the middle, behind and bafe of the abdo¬ 
men with yellowilh hairs. It inhabits Georgia. It de- 
pofits its eggs in the (kins of hares and rabbits. It is 
twice as large as the CE. bovis. The fidesof the abdominal 
fegments are yellow'; the body beneath is black. The 
larvae are brown ; every-where rough, with very minute 
prickles. 
7. CEftrus buccatus : grey; face white, dotted with 
black. It inhabits Carolina, and is a large infect. 
8. CEftrus tarandi : the wings of this fpecies are imma¬ 
culate ; thorax yellow, with a black band ; the abdomen 
is fulvous, tipt with black. It inhabits Lapland. De- 
pofits its eggs on the back of rein-deer, w hich produce 
larvae that are often fatal to them. 
9. CEftrus trompe: wings white; body black, with ci¬ 
nereous hairs; thorax with a deep black band. It inha¬ 
bits Lapland, and on the rein-deer. 
10. CEftrus antilopte : wings with a brown band and 
dots; body hairy, tawrvy-grey ; abdomen with three row-s 
of blackilh fpots. It inhabits Alia, and depofits its eggs 
on the back of the antelope. 
n. CEftrus fafciculofus: downy,yellow ; tail with three 
tufts of blackifn hairs. This is a Siberian infeCt. 
12. CEftrus hominis: body entirely brown. It inhabits 
South America. It depofits its eggs under the Ikin, on 
the bellies of the natives. The larva, if it be difturbed, 
penetrates deeper, and produces an ulcer, which fre¬ 
quently becomes fatal. 
13. The zimb. The formidable African fly defcribed 
by Mr. Bruce under the name of zimb, or tfalt-Jalya, may 
perhaps be referred to this genus; at leaft there are fome 
particulars in its hiftory which would lead one to fuppofe 
it an CEftrus. 
“ This infeCt (fays Mr. Bruce) is a proof how' falla¬ 
cious it is to judge by appearances. If we confider its 
Vol. XVII. No. 1187. 
finall fize, its weaknefs, want of variety or beauty, no¬ 
thing in the creation is more contemptible and infignifi- 
cant. Yet, pajfing from thefe to his hiftory, and to the 
account of his powers, we mull confefs the very great in- 
juftice we do him from want of confideration. We are 
obliged, with the greateft furprife, to acknowledge, that 
thole huge animals, the elephant, the rhinoceros, the lion, 
and the tiger, inhabiting the fame woods, are ftill vaftly 
his inferiors ; and that the appearance of this fmall infeCt, 
nay, his very found, though he is not feen, occafions 
more trepidation, movement, and diforder, both in the 
human and brute creation, than w’ould whole herds 
of thefe monftrous animals collected together, though 
their number w'ere in a tenfold proportion greater than 
it really is. This infeCt is called zimb; it has not been 
defcribed by any naturalift. It is in fize very little 
larger than a bee ; and its wings, which are broader than 
thofe of a bee, placed feparate, like thofe of a fly : they 
are of pure gauze, without colour or fpot upon them ; the 
head is large ; the upper jaw or lip is ffiarp, and has at the 
end of it a ftrong pointed hair of about a quarter of an 
inch long ; the lower jaw has two of thefe pointed hairs; 
and this,pencil of hairs, when joined together, makes a 
refiftance to the finger nearly equal to that of a ftrong 
hog’s briftle ; its legs are ferrated in the infide, and the 
whole covered with brown hair or down. As loon as this 
plague appears, and its buzzing is heard, all the cattle 
forfake their food, and run wildly about the plain, till 
they die, worn out with fatigue, fright, and hunger. No 
remedy remains for the refidents on fuch fpots but to 
leave the black earth, and haften down to the fands of 
Atbara, and there they remain while the rains laft, this 
cruel enemy never daring to purfue them farther. Ac¬ 
cordingly, all the inhabitants of the fea-coaft of Melinda, 
down to Cape Gardefan, to Saba, and thefouthof the 
Red Sea, are obliged to put themfelves in motion, and 
remove to the next land in the beginning of the rainy 
feafon, to prevent all their ftock of cattle from being 
deftroyed. This is not a partial emigration ; the inhabi¬ 
tants of all the countries from the mountains of Abyffi- 
nia northward, to the confluence of the Nile and Aftabo- 
ras, are once a-year obliged to change their abode, and 
feek protection in the fands of Beja; nor is there any al¬ 
ternative, or means of avoiding this, though a hoftile 
band were in their way, capable of fpoiling them of half 
their fubftance. 
“ Of all that have written upon thefe countries, the 
prophet Ifaiah alone has given an account of this animal, 
and the manner of its operations : And it /hall come to 
pqfs in that day, that the Lord Jhall Infs for the fly that is in 
the uttermojl part of the rivers of Egypt. And they Jhall 
come, and Jhall reft all of them in the defblate valleys, and in 
the holes of the rocks, and upon all thorns, and upon all bujhes. 
Ifa. xvii. 18, 19.”—By the expreffion of reding in the defo¬ 
late valleys, &c. Mr. Bruce underltands the prophet to 
mean, * that they ftiall cut oft' from the cattle their ufual 
retreat to the delert, by taking pofieffion of thofe places, 
and meeting them where ordinarily they never come, and 
which therefore are the refuge of the cattle.’ 
“ Providence, (fays Mr. Bruce,) from the beginning, it 
would l'eem, had fixed its habitation to one fpecies of foil. 
It prohibited abfolutely thofe inhabitants of the fat eartli 
called mazaga, domiciled in caves and mountains, from 
enjoying the help or labour of any beafts of carriage. It 
deprived them of their flefti and milk for food, and gave 
rife to another nation, whole manners were juft the re- 
verfeof the firft. Thefe were the Ihepherds, leading a 
wandering life, and preferving thefe immenfe herds of 
cattle by conducting them into the fands beyond the 
limits of the black earth, and bringing them back again 
when the danger from the infeCt was over. 
“We cannot read the hiftory of the plagues which God 
brought upon Pharaoh by the hands of Moles, without 
flopping a moment to confider a Angularity, a very prin- 
5 O cipal 
