30 The Philippine Journal of Science i9i3 



breeding jar and kept in individual test tubes. Two days later, 

 April 13, eggs were found in both tubes. These flies had 

 emerged April 4 and had been fed daily on a monkey. Their 

 actual age at the time of egg laying was 9 days. Another 

 fly which emerged from its puparium on March 21 laid its batch 

 of eggs, 81 in all, on March 30, when 9 days old. 



Nvmher of eggs laid by a single Stomoxys. — Under normal 

 conditions the eggs of Stomoxys calcitrans are laid in the manure 

 of its host. The eggs have been found in the faeces of the 

 horse, the carabao, the bullock, and no doubt are to be looked 

 for in the faeces of all domesticated animals. Under laboratory 

 conditions guinea-pig manure offers the best medium for egg 

 laying and subsequent development. In the laboratory, under 

 artificial conditions, this insect deposits its eggs in ordinary 

 glass tubes and on filter paper under glass. These ova hatch 

 in due time if moisture be furnished them. 



In order to determine accurately the number of eggs laid by 

 a single female, not much reliance could be placed on observa- 

 tions under field conditions ; therefore, it was necessary to resort 

 to experimental procedure. At first captive gravid flies were 

 used for this investigation ; then an attempt was made to verify 

 the findings with flies bred and mated in the laboratory. 



The flies collected in the open were usually taken from healthy 

 work animals and placed at once in test tubes plugged with 

 cotton. By using numbers of females of various ages, it was 

 hoped to obtain approximately the number in one which had 

 not yet made an initial oviposition. From these eggs flies were 

 reared for the purpose of checking the total oviposition in the 

 wild flies. 



Under these artificial conditions the females laid eggs in 

 the glass tubes beginning as early as the second day of their 

 captivity. The greatest number of eggs laid at one deposition 

 was 94, while 5 flies laid respectively 82, 86, 91, 91, and 94 eggs. 

 In every instance the eggs laid proved fertile, and the larvae 

 from them were transferred at once to breeding jars with 

 suitable food. 



The flies used for this study were kept in the dark at a uniform 

 temperature not exceeding 22° C. They were transferred daily 

 to clean vessels and fed on monkeys and guinea pigs. Seven 

 of the number which survived beyond ten days furnish the 

 following data: Egg deposition extended over a period which, 

 in 3 instances, comprised the entire life of the flies during 

 captivity ; in 2 others, to within three and four days of the death 

 of the flies. Two flies escaped after having laid, respectively, 

 446 and 438 eggs. 



