Published online by Cambridge University Press: 10 July 2009
1. More than twenty new forms and variations of tsetse traps are described in this paper for trial, and rejection or improvement, by other investigators. The species of tsetse-flies that they have been tested against have been palpalis, pallidipes, morsitans and swynnertoni.
2. The reactions of the various tsetse-flies to different forms of trap vary in a marked manner. Thus a trap (the Harris) that is excellent for pallidipes has appeared less good, though fair, for palpalis, poor (except at one season) for morsitans, and useless for swynnertoni. Another (the SS and the SSB) is particularly excellent for palpalis, excellent for pallidipes, mediocre for swynnertoni, and perfectly useless for morsilans.
3. Tsetses, pallidipes in particular of the two species tested, have been found to react also most strongly to the scent of an invisible animal placed in a trap. It is not known yet whether this attracts at a distance or is merely a close-range attraction, inciting the flies that have arrived in any case to such effort as takes them in larger numbers into the traps, but the latter does undoubtedly happen.
4. If the attraction be long-range, the flies do not readily distinguish between the source of the odour and conspicuous objects within its range. They go to and into a trap, even a trap that usually does not catch them, in greatly enhanced numbers when cattle are in its neighbourhood.
* This does not conflict with the fact that, at very close quarters, the most attractive part of the screen of a catching-cage trap is the black strip at the top. This at least appears to apply to pallidipes, palpalis and swynnertoni. There have been indications that morsitans prefers grey even here.
* Indications have been obtained since and a number of other new conclusions have been arrived at by Mr. W. H. Potts, Senior Entomologist, continuing the trapping in Shinyanga. These will be published later.
* For the crinoline trap see, inter alia, Government of India Health Bulletin, no. 11, 1927.