The mosquito proboscis is involved in host recognition. (A) Schematic of host recognition assay (see Materials and Methods). 120 female mosquitoes were divided into two groups, intact (control) and appendage-ablated (experiment). Mice were placed individually into indicated cages and monitored simultaneously by counting the number of mosquitoes sucking blood. (B-F) To determine the contribution of each appendage to host recognition, each group of female mosquitoes lacking specific body parts (leg, antennae, maxillary palps, or proboscis) was prepared for the assay shown in (A). The proportion of mosquitoes touching down on mice was calculated every 0.5 min for 7 min. Blue bars represent controls while other colored bars represent experimental groups. Note that a mosquito's ability to recognize a host is clearly reduced upon removal of the proboscis (E and F). (F) **p < 0.005, ***p < 0.001, t-test; mean ± SD, n = 4.