Rate and quantity of delivery of venom from honeybee stings.

To determine the rate and completeness of delivery of venom from honeybee stings, European bees were collected at the entrance of a hive and studied with the use of two laboratory models. In one model bees were induced to sting the shaved skin of anesthetized rabbits. The stings were removed from the skin at various time intervals after autotomization, and residual venom was assayed with a hemolytic method. In the other model the bees were induced to sting preweighed filter paper disks, which were weighed again after removal of the sting at various intervals. Results of both experiments were in agreement, showing that at least 90% of the venom sac contents were delivered within 20 seconds and that venom delivery was complete within 1 minute. The data suggest that a bee sting must be removed within a few seconds after autotomization to prevent anaphylaxis in an allergic person. The extensive variation found in the amount of venom delivered at each time point may explain inconsistencies in relationships among reactions to field stings, sting challenge testing, venom skin tests and RAST.

Autogeny in Culex salinarius from Texas, Florida and New Jersey.

Autogeny was studied in Culex salinarius from College Station, Texas; Vero Beach, Florida; and Edison and Dennisville, New Jersey. Autogenous egg development varied from 14% in the Florida colony to 23 and 27%, respectively, in colonies from Texas and New Jersey. The mean number of eggs per autogenous female ranged from 13.5 to 23.7. As in other autogenous mosquitoes, the expression of autogeny was dependent on larval and adult diets. Mating did not influence autogeny as it does in some mosquitoes. Autogeny in Cx. salinarius was obligate at warm temperatures, but females denied a bloodmeal appeared to undergo facultative autogeny at colder temperatures.