147 



parasitism by the Chalcid took place after 29th April. The extent of 

 infection by Braconids, in the absence of Chalcids, reached 90 per cent. 

 These parasites are therefore of great importance in limiting the 

 numbers of flies. The Chalcid, M. acasta^ was always found in puparia 

 which were already attacked by a Bracomd and this species may there- 

 fore be a hj^erparasite. In one case the e.^g of M. acasta was found 

 attached to the abdomen of a pupa of Aphaereta cephalotes within a fly 

 puparium. The hfe-cycle of M. acasta occupies about a month. 

 Hibernation takes place in the larval stage in the fly puparium. 



Parker (R. R.). Dispersion of Musca domestica, Linnaeus, under 

 City Conditions in Montana. — Jl. Econ. Enfom., Concord, ix, no. 3, 

 June 1916, pp. 325-354, 7 plates, 4 tables. 



This paper gives details of the experiments recorded in a paper 

 already abstracted [see this Review, Ser. B, iv, p. 78]. 



A bibliography of 11 works relating to the subject of fly dispersal is 

 appended. 



Evans (A. T.). Some Observations on the Breeding Habits of the 

 Common House-Fly, Musca domestica, Linnaeus.— JL Econ. 

 Entom., Concord, ix, no. 3, June 1916, pp. 354-362. 



Musca domestica was found to breed readily in fresh horse manure, 

 rarely in cow manure, and in one instance only in garbage. The 

 migration of the larvae to the outer layers of manure heaps was 

 observed. Failure to oviposit in garbage was shown to be due to the 

 acid nature of this substance. Manure, when tested, was found to be 

 alkaline ; samples which had been standing for 30 minutes contained 

 0"647 per cent, of ammonia, but this quantity decreased as the exposure 

 became more prolonged. The percentage of acid in garbage varied, 

 but on an average was sufiicient to neutralise an equal quantity of 

 ammonia of a strength of 0"653 per cent. Eggs and larvae were able 

 to develop normally in manure soaked with ammonia up to a strength 

 of 0"7 per cent., but practically no development took place in the 

 presence of hydi'ochloric acid, even when very dilute. Pupae placed 

 in earth moistened with distiUed water, 0*75 per cent, acid, or 2"1 per 

 cent, ammonia, completed their metamorphosis in a normal manner. 

 Oviposition took place on old rags which had been previously 

 moistened ; the larvae hatching from these eggs migrated from the 

 rags in the absence of a food supply. Attempts to induce egg-lapng 

 in manure moistened with liquid from garbage met with negative 

 results. In all the experiments it was noted that the larvae were 

 sensitiA'e to excess of moisture, while in manure heaps and bins they 

 were always present in the drier portions only. The scarcity of larvae 

 in cow dmig may be attributed to the saturated nature of this substance. 

 Adult flies which occurred abundantly near garbage seemed to visit 

 it for feeding purposes only. 



The lar\-icidal properties of hydrochloric acid at a strength of from 

 0"75 to I'O per cent, suggest its value as a spray for use against the 

 breeding places of flies. 



