Heterocloeon curiosum McD. (1923)

The reduced median caudal filament of the nymph and the presence of a metathoracic wing in the adult would place this species in the Acentrella subdivision of the genus Baetis. This nymph is one of the commonest in the streams investigated but is confined to the lower, warmer reaches.

In 1932, severe defoliation of alders (Alnus rubra Bong.) in Stanley Park, Vancouver, drew attention to a sawfly, Hemichroa crocea Geoff., which was responsible for the damage. More extensive infestations have occurred during the past six years on alder in the lower Fraser Valley. In Europe, the species has been known for a long time as a defoliator of various species of alder (W. Konow, Chalastogastra, 1901-1905). In 1936, R. Glendenning of Agassiz, B. C. said in a letter that he had found the larvae causing some injury to cultivated filberts.

Several years ago the writer received, for determination, several specimens of a species of Coenonympha from Oregon. These specimens turned out to be Coenonympha ampelos Edwards. They were taken in August. Comparing these August specimens with a large series of specimens taken during the latter part of May and early June, I found that the two broods of ampelos were different. The summer brood was slightly lighter in color and much browner, with very little of the dark powdering found on the underside of the secondaries in the spring brood.

This North American genus was erected in 1864 by Loew who based his description on specimens collected in New Hampshire. The species of this genus are readily separated from those of any other chironomid genus by the presence of a median longitudinal fissure on the mesonotum. The nonplumose male antennae are also quite characteristic of this group, although this condition obtains also in the genus Hydrobaenus Fries. At present five species are known, to which are now added three new species.