SHEEP SPIDER FLY. 119 
Sheep Spider Fly or “Sheep Tick.” Melophagus ovinus, Linn. 
os 
MELOPHAGUS ovINUS and puparium, nat. size and magnified (puparium showing 
dried adhesive coating). 
The Sheep Spider Fly, or ‘‘ Louse Fly,” or ‘Sheep Tick,” as it is 
commonly e¢alled, is an infestation closely resembling that of the 
Forest Fly, both in its method of propagation and its habits. It only 
lives actively in fly state, and multiplies, not by egg-laying or deposit 
of ordinary maggots, but by deposit, or laying, of squarish bright 
chestnut-coloured pupa-cases, from which the flies presently emerge, 
and feed by blood-sucking. 
The infestation is not so troublesome in some respects as that of 
Forest Fly, for the ‘Sheep Ticks’’ have not the power of running as 
fast as they can go, backwards, forwards, or sidelong, scraping and 
dragging amongst the fine hair, and on the tenderest parts of the skin, 
but, on the contrary, move slowly and quietly in the wool. Also, as 
these Spider Flies are wingless, there is no alarm given by sudden 
attack and burrowing in the hair, neither can the infestation be spread 
except by the flies crawling from one animal to another, as for instance 
from sheep to lambs, or to the animals lying on pasturage where the 
chrysalids or pupa-cases have dropped from the sheep, and the flies 
crawl to them on hatching. 
In the course of last season such a good supply of live specimens 
was sent me, in wool from fleeces of sheep that had not been dipped, 
as to enable me to study them and their peculiar chrysalis-case per- 
sonally; and though with this attack the requisite treatment is so 
thoroughly known that any suggestions are quite uncalled for, some 
short notes of the life-history of the fly itself may be of interest. 
It should perhaps be observed that, though the name of ‘ Sheep 
Tick” is so commonly and universally bestowed on the pest, at least 
in Europe and America, as well as in this country, it may be said to 
be the established name, still, really, it is not a ‘‘Tick” atall. The 
difference may be easily told by noticing that, except in its very earliest 
state, a true Tick has eight legs, and also it has no marked division 
between the fore body and abdomen (see figures of ‘‘ Ticks’”’). 
The Sheep Spider Flies, or ‘Sheep Ticks,’’ scientifically Melo- 
