Diplolepis utahensis

Rosa sp.
"Root" galls
Deeply incised on top, half-buried, up to 55 mm in dia. When mature light in weight, spongy within, the larval cells deeply buried.

[Photo caption]

334. On Rosa sp. Adults emerged May 12-June 1 (Chi).

Diplolepis utahensis (Bass.).

Rosa sp
At surface of ground, up to three inches in diameter, deeply cleft above . S. Utah.

Rhodites utahensis n. sp.

Mr. Siler sent me from Utah, several years ago, some very large rose galls that did not differ, so far as I could see, from R. radicum O. S. It is true they were larger and less regular in form than that species and showed more plainly that they originated in a leaf bud. The largest specimen was three inches in diameter, and one or two others were nearly as large. They appeared to have grown near the surface of the ground, but not under moss or fallen leaves, as is the habit of R. radicum. They were old galls and I reared nothing from them, but on cutting them open I found several perfect insects, evidently Rhodites, and all of the male sex. The females seemed to have made their way out. On comparing them with the males of R. radicum I found them to agree so closely that I was disposed to look upon them as merely a variety of that species. Further study revealed some minor differences, and at least one characteristic that seemed to entitle them to rank as a distinct species.

There are species in this genus that resemble each other more nearly than these two, but in such cases the galls are very distinct. If further observations show it to be only a variety it is sufficiently marked to deserve a name.

Diplolepis radicum variety utahensis (Bassett)

Rhodites utahensis

GALL. — Does not differ particularly from the galls of other varieties; averages larger.

RANGE.— Utah: Thistle (Weld collector); Provo, Price.

Bassett described utahensis from several males cut from old galls sent by Mr. Siler ''from Utah". The original de- scription was a brief comparison of the males with "radicum'', but such a comparison as would cover several of the western varieties, especially since it cannot be entirely certain which of the eastern varieties Bassett had in mind. As with other Cynipidae, there are probably several varieties of this species to be found in Utah, and I have no other reason for taking my Provo and Price material to represent Bassett's name than that this is the common variety in a large part of the more accessible regions of that state. This material does not disagree with anything in the original description. Altho the types are lost it may be as well to retain the Bassett name, restricting it as I have.

Of 4077 insects I have bred of this material, 2554, or about 63 per cent, are males. This high percentage is evidently due to the premature collecting of the galls which appears to pre- vent a larger number of the less mature females from emerging. Of the first 2948 Provo insects emerging 69.5 per cent were males; of the last 765 Provo insects emerging only 49 per cent were males. More mature galls collected at Price gave only 38 per cent males. These factors in obtaining ratios of the sexes of Cynipidae must be borne in mind if we are to avoid wrong conclusions. It is safe, however, to estimate that the males are about equal in number to the females in this species. The adults emerged after collecting on April 18 and April 20, 1920. As with other species in this genus this insect probably has no alternation of generations.

A part of the material from Pullman, Washington, matches this Utah material very closely, but until I can examine further collections I should hesitate to state that the range extends into Washington. Beutenmuller's 1907 description of utahensis was made from this Washington material, which is at least in part another variety, diver gens.