Use of a modified chemical transfer pump for sampling Culiseta melanura larvae.

The cryptic nature of Culiseta melanura larval habitats has limited the use of the conventional one-pint dipper for enumerating the larval density of this species. A modified chemical transfer pump was used in a survey of a known breeding swamp. Field trials assessed the practicality and potential biases towards instars in open vs. closed crypts. From 148 samples taken at 37 sites, 631 Cs. melanura larvae were collected. Closed crypts accounted for 21% of the positive samples. The pump had utility in the field but a relative scarcity of 4th-instar larvae in the samples may indicate a source of bias toward younger instars.