The larvae of these three mites are described for the first time.

1. - Aturus scaber Kramer.

Females of this species lay one, very large egg at a time, suggesting a suppression of the larval stage and direct development to nymph. This expectation has been refuted and the larvae bred in the laboratory. Further information on the life-history is lacking but a parasatic stage is indicated.

2 . - Piona uncata Koenike.

The complete life-history of this mite is described. In the specimens studied the main host was Chironomus plumosus L. Work by Stout shows that this species has an alternative direct development. The larvae are similar except in size to those of P. coccinea Koch.

3. - Protzia eximia Protz.

Eggs are found throughout the winter and laboratory tests show that hatching is dependant on temperature. The larvae resemble those of Panisopsis species, and run actively on the water film. They are able to jump 2 cm from the surface and use this ability to gain a place on their hosts, an unidentified Trichopteran and the fly, Weidemannia bistigmata Curtis. There are probably two generations a year.

An up-to-date table gives hosts for 150 species and references for this information.