'j^ The Irish Naturalist. July, 



feeding calves — otherwise preserved from infection — with 

 eggs or young larvae of the warble-flies ; and also to see 

 if young larvae observed to have bored in through the 

 skin could be proved to ripen under carefully controlled 

 conditions, no other infection of the experimental cattle by 

 Hypoderma being allowed. Trials on both these lines were 

 made, and while those testing entrance by the mouth were 

 entirely negative in result, those with the boring-in maggots 

 were conclusively positive. The experimental work was 

 carried out with great care and skill by my late colleague, 

 Thomas Slattery, A.R.C.Sc.L 



During the summer of 1915 six calves were fed with 

 100 young maggots each and one with 45. Three of these 

 animals were slaughtered in the autumn, but no second 

 stage larvae were found in their gullets. The remaining 

 four were found to be entirely free from ripe warble 

 maggots in the succeeding spring. 



In the course of the same summer three housed calves 

 at Athenry had a number of maggots that had just been 

 hatched in an incubator placed on the skin of each — over 

 the hip or shoulder, or on the hock. Nearly a hundred 

 larvae were placed on each of two calves, and forty on the 

 third. Two of these animals were killed in October, and 

 a single second-stage maggot was found in the sub-mucous 

 coat of the gullet of one of them. The third had no ripe 

 warble-maggots next spring. It appeared that experimenting 

 with incubated larvae might be too unnatural a mode cf 

 working, so during the fly-season of 1916 at Athenry four 

 calves, kept continuously in the house, had eggs, laid by 

 captive flies, bandaged on to their legs under celluloid 

 strips, while four others were taken on one day only into 

 a field where cattle were grazing and " gadding," and 

 tied up for an hour in a small enclosure imder close 

 observation, their bodies completely covered by clothing 

 except the hind limbs on which flies could therefore laj^ 

 eggs under natural conditions. The results proved most 

 interesting. None of the cattle on whose legs the eggs 

 had been bandaged had any ripe marble-maggots next 

 spring. Here again the conditions were evidently too 

 abnormal for success. But of the four on which eggs w^ere 



