This letter questions the appropriateness of methodology used in a study by Howard and Oliver (J. Am. Mosq. Control Assoc. 13:315-325; 1988). Two independent data sets, collected for different purposes by 2 different groups, were subjected to statistical analysis to determine if the data sets differed. The experimental "design," as described by the authors, is an example of pseudoreplication, which arises when replicates are collected at a scale finer than the one for which conclusions of statistical testing are intended to be drawn. All of the components of a properly designed field experiment (control, replication, randomization, and interspersion) are missing from this study. The authors proceed to draw a series of conclusions from the data presented. Few, if any, of the conclusions can be supported by the evidence presented. The assertions put forward in this paper could have a severe negative impact on efforts to prevent transmission of arboviruses or other pathogens to humans and domestic animals.