DIPTERA 



323 



Stomoxys nigra, Macq. 



Found in 1916 at St John's Lake, Auckland, by Mr D. Miller. 

 This is a South African species. 



Family (EsTRiDy^ 

 CEstrus ovis, Linn. Sheep Nasal Bot-Fly 

 Capt. Hutton recorded this first in Canterbury in 1 873 . Dr Hilgen- 

 dorf states that these flies are very common; and that in the back 

 country of Canterbury they trouble the merinos very much : 



"At the Cass on hot days," he says, "the sheep may be seen stamping 

 their feet, tossing their heads, or standing huddled together, with noses 

 to the ground; this is because the bot-flies have laid their eggs in their 

 nostrils." 



Dr Gilruth, reporting on the subject in 1899, stated that: 



flocks in New Zealand become affected without any previous agitation of 

 the animals having been noticed. In older countries the sheep become 

 very excited if even only one fly be in their vicinity. They suffer mostly in 

 autumn, the larvae lodging in the nasal passages and the bony sinuses of 

 the skull. 



The larvas have been known to cause rhinal myiasis (i.e. in human 

 beings). 



This fly is found in all parts of New Zealand. Dr Hilgendorf 

 considers that nearly every sheep harbours them. 



Gastrophilus equi, Meigen. Horse Bot-Fly 



Captain Hutton saw this species first in 1892, and for two or three 

 years they were very abundant and caused quite a scare. Dr Hilgendorf 

 considers that the damage they do to horses' stomachs is probably 

 insignificant, though the annoyance to horses when the flies are 

 laying their eggs is very great. He says: "Every horse we kill has 

 abundance of bots in its stomach." 



Mr Philpott says (1917) : 



The horse hot is very common now. Some horses are extremely restless 

 when the flies are about, but others take little notice. A few weeks ago I 

 saw a bay mare so covered with eggs about the legs and abdomen that at 

 a little distance she appeared to be tinged with grey. Her owner told me 

 that she never took the least notice of the flies. In the same paddock was 

 another horse which was continually walking to and fro, whisking its tail 

 and snapping vigorously at the insects. 



Gastrophilus hcemorrhoidalis, Meigen. Horse Bot-Fly 



Supposed to have been introduced by some Mexican circus-horses 

 from San Francisco; 'first noticed in the North Island in 1889, and 



