122 HUGH GLASGOW. 



Coreidse, as it very clearly did for those of the Pentatomidse, then 

 there was certainly very little encouragement to continue culture 

 work with these insects, for although strains of bacteria might be 

 isolated that would agree perfectly with the caecal bacteria in 

 their morphological characters, this would establish very little, 

 as there is nothing about the bacteria from the Coreidae to dis- 

 tinguish them in this way from many common saprophytic forms 

 that might readily gain access to the intestine of these insects. 



As the first two sets of culture tests were made from bugs that 

 had been kept in a warm room and had been feeding continually 

 up to a week of the time before the dissections were made, it 

 seemed possible that the antagonism of the coreid bacteria to 

 invading forms was not so absolute as in the Pentatomidae, and 

 that, if hibernating insects were used which had had no opportu- 

 nity to feed for a considerable period, the normal bacteria might 

 in this time have succeeded in effectually killing off the foreign 

 species. It was accordingly decided to attempt the cultivation 

 of the squash bug bacillus once more, hibernating insects being 

 used this time in the hope that as a result of long fasting their 

 normal bacteria might have eliminated the transient forms. 



For these tests, the insects were taken after the middle of 

 December from their winter quarters. They could not have fed 

 for at least a month; and they were dissected at once. Thirty- 

 five specimens of Anasa tristis were collected for this work and 

 every precaution was taken in the dissections and inoculations 

 to guard against, contamination from without. The insects were 

 sterilized before dissection with a thoroughness which would not 

 have been permissible with Murgantia; but ; notwithstanding 

 this, cultures were obtained from these insects as regularly as 

 they had failed where Mnrgantia was used, all thirty-five of the 

 tubes inoculated developing an abundant growth. 



These cultures were incubated at room temperature and were 

 watched closely for the appearance of any contamination. 

 Growth was found to appear rather tardily, developing in from 

 two to four days, and at first, as in the two previous series of 

 experiments, consisting of an apparently pure culture of a short, 

 motile organism which could not be distinguished morphologi- 

 cally from the caecal bacteria as taken direct from the insect. In 



