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 It is very doubtful if there is any alternation of generations within this genus. Adler (1881) has definitely proved, by the breeding of successive generations, that Diastrophus rubi has no alternation of generations, and nothing known concerning emergence dates, dates of appearance of the galls, etc., indicates that we should expect heterogeny in the group. Herein these insects are more primitive, less specialized than the oak gall-wasps.

This genus is clearly related to the genus Diastrophus, from which it is best distinguished by having the scutellum ending in a point which projects far over the metathorax. This indicates some degree of specialization beyond Diastrophus.

Another character which I feel is a good indication of specialization is the more complex character of the galls of Gonaspis. These galls are monothalamous and separable from the host plant (Diastrophus galls are polythalamous and inseparable) and show a considerable degree of separation of the zones, the epidermal layer in G. potentilla? being connected with the larval cell by distinct strands of tissue.

G. cuscutæformis also has a monothalamous, separable gall which is complicated with spinous processes, and the species evidently belongs in this genus, where Dalla Torre and Kieffer (1910) placed it. It has a scutellum which is more specialized than is usual in the genus Diastrophus and, although it is not as developed as in Gonaspis potentillæ, this character, taken in connection with the specialized gall of the insect, is enough to warrant considering the species to belong to Gonaspis.

Including Lytorhodites Kieffer

The radial cell in this genus is closed in thirty species, but it is more or less open in six species, R. arefactus Gillette, R. multispinosus Gillette, R. nebulosuts Bassett, R. neglectus Gillette, R. ostensackeni Beutenmüller, and R. semipiceus (Harris) [=R. fulgens Gillette]. The closed radial cell is found nowhere else in the family except in the group to which Aulacidea belongs, and it is not to be supposed that a closed-cell genus is evolved from other than a closed-celled genus. It appears that Rhodites is evolved, directly or indirectly, from Aulacidea or from a group from which they both originated. The species with the open radial cell show, in that respect, a higher development, and