The season of activity of P. pallipes begins about the last of April. My notes show that on April 24, 1920, a survey of the Wickes region discovered no wasp enterprises whatsoever; April 28 in 1921 found a few queens out on the flowers and a few just beginning their nests; the most progressive had completed three cells.

During the past four or five years, several puzzling specimens of a form of Euxoa closely related to plagigera and oblongostigma have been collected in various parts of Montana. Some examples were submitted to Dr. McDunnough in the writer of 1927-8, and he reported as follows:

This form has always puzzled me; it occurs in Utah and I believe it to be a brown form of plagigera but some run very close to oblongostigma and are very hard to separate without genitalic slides.

A study of the distribution of mosquitoes from Colorado discloses many areas which have not as yet been reported. Among the collections we find only one report of Anopheles and its identification has been uncertain. Cockerell lists seventeen species of mosquitoes from Colorado or Wyoming. Among these is listed Anopheles quadrimaculatus Say taken at Hotchkiss and Delta in Delta County by G. P. Weldon and recorded by Howard, Dyar, and Knab. He states: “We have so far found no trace of Anopheles in our collections.”

In 1928 the writer described in The Canadian Entomologist, volume LX pages 148 to 151, two species of fleas from Colorado under the names Ceratophylius peromysci and Ceratophyllus citelli. Recent studies have shown that both of these names are synonyms.

The hypothetical ancestor of the Aphididae was probably a large generalized form, always winged, both sexes occurring in each generation, and with only a few generations each year. Migration would be lacking, and the development of the aphid ancestor would probably be tied up with one of the primitive types of plants occurring in that early period.

This genus has been considered synonymous with Ludius Esch. but seems distinct by the following characters: form usually robust and strongly convex; front moderately convex, not margined; prothorax wider than long; elytrai striae moderately impressed at base, very feeble or obsolete elsewhere; prosternal lobe rather short; the prosternal process in lateral aspect very strongly arcuate between the coxae and with the apical portion strongly oblique; the prosternal sutures almost straight; coxal plates narrow, more or less narrowed externally; tarsi filiform, the claws simple. Type Limonius estriatus Lec.