A new aphid on guayule and notes on other species of Cerosipha

Abstract does not appear. First page follows.

On July 13, 1942, during an investigation of insects attacking guayule, Parthenium argentatum, in the United States government nurseries at Salinas, California, W. H. Lange discovered on some slightly wilted seedlings, a new root-infesting species of aphid. In preparing the description of this insect, comparisons had to be made with other known species of the genus Cerosipha to which it belongs. Since there is some confusion concerning the relatively few species relegated to this genus, enough descriptive and illustrative material has been included to make possible ready recognition of all the members.

The Guayule Aphid

Cerosipha californica n. sp.

Lange found the aphids in small bark and root cavities made by wireworms and other insects. Frequently but a single specimen occupied such a cavity. A thorough search revealed relatively few aphids present and on young nursery stock only. So far no more have been found in the nurseries and none at all in the older field plantings. In all, only 1 alate and 4 apterous mature parthenogenetic females, 12 young, and 7 nymphs were collected on guayule.

In my collection there was also a single balsam slide mount containing 3 alates of a species taken on the leaves of French prune in the orchard of the University of California, Davis, on November 8, 1928. These alates were labeled Cerosipha sp. In order to study them better they were cleared and remounted in euparal, a single specimen to a slide. In all respects they appear to be identical with the single alate taken on guayule and are treated as paratypes of the species.

Additional specimens of this species were recently taken on the roots of potatoes at Bakersfield, California, on May 8, 1944, by Gordon L. Smith.

In checking over some mounted specimens collected by W. C. Look on tomato at the Waipaha School Gardens, Waipaha, Oahu, Territory of Hawaii, September 9, 1940, I find that three alate specimens provisionally determined as Vesiculaphis caricis (Full.) prove to be this species. An important variation in the wing venation is the frequent extension of the second fork of the media vein to almost the margin of the wings as in one specimen and its omission as