H. Eltringham 455 



la Experiment XIII in which the heap was enclosed on August 30th 

 there was ever_y opportunity for il/. domeslica to breed. The heap was 

 continually watched before covering in and it is certain that M. dumestica 

 did not visit it in great numbers. The small maggots destroyed by the 

 heat were probably those of the Limnophoia, and in any case the heat 

 would not account for the small number of M. domeslica since similar 

 conditions obtained in Experiment II. The results obtained with 

 heaps at the farm buildings were more interesting. The first three 

 heaps produced no examples of M. domestica, nor was it an easy matter 

 to find this species in or about the stables. Later on the fly appeared 

 in some numbers and random catches with the net gave the following: 



Musca domestica L. ... ... 44-4 % 



Miisca autumwdis De G. ... 31-48 % 



Miiscim stahiihnis^hx ■24-08% 



To these figures, however, I cannot attach very great imp(}rtance 

 since from Experiment IX it woidd seem that Stoiiio.rijs calcilmiis 

 should have been the commonest fly, whereas none were taken in the 

 net. On August 12th I inspected adhesive fly-papers in one of the 

 cottages already referred to as near the farm buildings. One of these 

 papers, stated to have been in use about a fortnight, had caught some 

 300 flies, almost all M. domestica. Another paper in use for the same 

 period contained perhaps a few more. Careful search failed to disclose 

 any special nidus for these flies. The most likely place seemed to be the 

 garbage pit referred to in Experiment XVIII. Although flies of many 

 species were obtained from this pit only one proved to be M. domestica. 

 From other experiments it may be assumed that a few of the flies taken 

 on the fly-papers came from the permanent manure yard at the farm 

 buildings. There is nevertheless a strong temptation to suppose that 

 with the well-known tendency of the species to enter houses, the 

 cottages in question formed an attraction for every wandering fly in 

 the neighbourhood and they were thus more hkely to be found there 

 than elsewhere. Heap 4 having produced no house-flies from the first 

 filling, a second supply of fresh horse manure was trapped but without 

 producing M. domestica. Heap 5 treated in the same way produced 

 altogether 11 of this species. Meanwhile endeavours had been made 

 to find the fly breeding in the large permanent heap already referred 

 to. In Experiment IX 3 M. domestica were taken together with 

 about 453 Stomnxys calcitrans, whilst from another part of the same 

 heap (Experiment XVI) 16 specimens of the former were secured. The 



