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VOLUME 27, NUMBER 3 225 different lengths, tipped with darker gray. Hindwing pale yellowish-white, darkened near apex and, in the female, along outer margin. Beneath: forewing yellowish-gray, hindwing yellowish-white. Wing expanse: 21 to 24 mm. Holotype: Male, Big Bend National Park, Green Gulch, Texas, 28 March 1971, gen. prep. A.B. 3030, deposited in the National Museum of Natural History, (No. 72380). Paratypes: All from Big Bend Nat. Park, Green Gulch: 9 October 1969, 1 ~, (A.B. 2011); 28 March 1971, 5 ~ ~, (A.B. 3030, 2649, 2650); 3 May 1972, l<j>, (A.B. 3029); 12 May 1972, 1~, 1<;l, (A.B. 3028). ACKNOWLEDGMENTS I am deeply grateful to Dr. D. C. Ferguson of the Entomolgy Research Division, U.S.D.A., for revising the manuscript and making several very helpful suggestions. The authorizations given me by Mr. C. D. Laughlin to collect on the McDonald Observatory grounds, and by the Administra­ tion of Big Bend National Park to collect around and in the Chis os Mountains are also gratefully acknowledged. LITERATURE CITED HEINRICH, C. 1956. American Moths of the subfamily Phycitinae. U.S . Nat. Mus. Bull. 207. NOTES ON THE TAXONOMIC STATUS OF HYALOPHORA COLUMBIA (SATURNIIDAE) MICHAEL M. COLLINS 924 Mendocino Avenue, Berkeley, California 94707 The work of many authors (Sweadner, 1937; Weast, 1959; Collins & Weast, 1961; Wright, 1971) has shown that the various forms of Hyalophora are not reproductively isolated from one another. Females of any form of Hyalophora (in the restricted sense of Ferguson, 1972) will attract and mate indiscriminately with males of any other form. f Generally ova laid by cross-mated females are viable and usually produce I fertile F 1 males and sterile females. Backcrossing the F 1 male with a female of either parental form or even a third form again produces fertile males and generally sterile females. Occasionally these females may lay some fertile ova. Intergrades and hybrids occur in nature. A population currently des­ ignated "kasloensis" (Cockerell) exists between H. gloveri (Strecker) and H. euryalus (Boisduval) in Idaho, western Montana, and British 226 JOURNAL OF THE LEPIDOPTERISTS' SOCIETY Columbia and is believed to be an intergrade between these two forms. H. cecropia (Linnaeus) produces occasional hybrids with gloveri. I obtained such an individual when a hybrid-like cocoon collected along with typical gloveri in the Black Hills of South Dakota produced a female very similar to laboratory hybrids. Mr. Duke Downey (pel's. comm.) has collected supposed hybrids in Sheridan, Wyoming, but only rarely. The contact between gloveri and cecropia may be the recent result of a west­ ward invasion of the latter species (Cockerell, 1929; Peterson & Worden, 1962). Wild hybrids between H. columbia (Smith) and cecropia have been cited by Sweadner (1937). I collected a hybrid male along with typical columbia one mile west of Whiteshell Provincial Park along Highway One in Manitoba on 18 June 1963. This specimen will be described in a later paper. No true blending occurs between cecropia and the other forms but introgression is indicated by columbia and gloveri specimens with red scales in the extradiscal band. About half the specimens of gloveri and columbia sampled by Sweadner in areas of contact with cecropia exhibited this trait. The density of recognizable hybrids in nature is lower than predicted from the results of laboratory crosses. In addition, the mobility of the males during the mating flight and of the females during oviposition assures a potentially high rate of gene flow. Selection must act strongly against hybrids in some way. Hybrids may be ill-adapted such as in oviposition habits and consequent foodplant acceptance. H. columbia spins a small cryptically colored cocoon on exposed tamarack branches. W'hen cecropia breeds with this form the larger non-cryptic hybrid cocoon may be more easily found by predators. Given the ability of the Hyalophora forms to intergrade, the origin and present status of columbia seemed to be an excellent subject for study. In the United States gloveri is quite distinct phenotypically and is separated geographically from the small dark form in Maine, Wisconsin, and Michigan designated columbia. In western Canada the gloveri popu­ lation exhibits a phenotype nearer to columbia in size but often even more brightly colored than the Rocky Mountain phenotype. Consequently, gloveri and columbia have up to now been considered separate species. On the basis of geographic distribution, wing pattern, and identical genitalic structure, Sweadner believed columbia arose from gloveri at the end of the last period of glaciation. To account for the apparent lack of intergradation, he believed the two became geographically isolated by foodplant preference. The gloveri population in the prairies of Alberta, Saskatchewan, and Manitoba, which has been given the subspecies name nokomis, feeds on wolf willow (Shepherdia) and to a lesser extent on willow (Salix). The Hyalophora in the swamps east of Winnipeg, VOLUME 27, NUMBER 3 227 recognized as columbia, is thought to feed entirely on tamarark (Larix). These food plants are not isolated, however. The Shepherdia of the plains meets to the north a broad band of spruce-tamarack forests ranging from British Columbia across Alberta and Saskatchewan to Manitoba where the conifers dip south to the east of Winnipeg (Harlow & Harrar, 1949). Thus, a foodplant bridge connects the two populations but at a more northern point than was sampled by Sweadner. Field Work I conducted field research in Canada in 1963, 1964, and 1966 to better sample these populations. Tied females and females in specially designed moth traps were placed at intervals throughout selected areas. The moth trap consists of a nine inch metal funnel mounted at one end of a screen cylinder two to three feet high. A small cage is suspended above the mouth of the funnel and confines a H yalophora female. Attracted males, in their frenzy to reach the female, eventually collide with the funnel and slide through its enlarged opening. Thus, several males can be taken at each site and the female can be used as bait for up to 4 or 5 days. Three population areas were sampled. The general trap line was along Highway One east and west of Winnipeg. The small dark phenotype was first taken just outside of the tamarack bog 30 miles east of Winnipeg near Richer. Thirty-two specimens were taken at regular intervals up to the Manitoba-Ontario Border beyond which no traps were placed. No males of any form were collected beyond the western extent of the bog 30 miles east of Winnipeg to a point 90 miles west of Winnipeg. Shep­ herdia does not seem to occur in this immediate area and extensive farming must further isolate the two Hyalophora forms. Stands of Shep­ herdia occur west of here along fence rows and in untillable terrain. To the west the first male of the brightly colored phenotype was taken 26 miles east of Brandon, Manitoba. A total of 17 specimens was taken westward along Highway One to Swift Current, Saskatchewan. The only cecropia collected was trapped 5 miles west of Virden, Manitoba on 21 June, 1963. In an attempt to collect a predicted intermediate form between gloveri and columbia, I collected north along Highway Ten to Flin Flon, Mani­ ~ toba and then west to Prince Albert Park, Saskatchewan. The terrain I near Flin Flon is unusual in that the tamarack bog is interrupted by granite outcroppings and the flora is consequently more varied. Shep­ herdia was not seen near Flin Flon. The possible implications of this environmental change was discussed below. Frequent cold weather limited collecting but 12 males were taken from 17 to 22 June, 1964. 228 JOURNAL OF THE LEPIDOPTERISTS' SOCIETY VOLUME 27, NUMBER 3 229 Analysis of Specimens When the population samples collected were compared superficially, it was clear that not all specimens could be placed into one of two distinct phenotypes. Furthermore, the light and dark moths were not always associated with the expected foodplant community. One of the males from the tamarack bogs east of Winnipeg was as brightly colored as the average Shepherdia-feeding phenotype and at least one of the specimens from the latter population was quite as dark as those from east of Win­ nipeg. Sweadner reported similar specimens from the large samples he secured. The moths taken from the north were quite variable; some were as dark as those from east of Winnipeg and others were as bright as the prairie phenotype. Most were intermediate in coloration (Fig. 1). To present a more objective comparison, I quantified this color variance and analyzed it statistically. While the more northern sample was somewhat small, I believe the results are significant. The ground color of the dark phenotype is usually accompanied by a darkening of the color band distal to the white wing band. Under the microscope one sees that this dark­ ening is the result of an increase in the number of black scales relative to the number of white scales. Using a magnification of 40x with a grid reticle I measured the relative scale density in this band contained in the cell formed by veins CUl and M3 • The total numbers were con­ verted to percentages and then plotted as a distribution with the mean and standard deviation. Fig. 2 shows that the specimens from northern Manitoba are more variable than those from east of Winnipeg and are very intermediate for this character. Surprisingly, the moths from northern locales were larger on the whole in both average and maximum size than specimens taken further south. Males collected east of Winnipeg (32 specimens) averaged 50.3 mm measured from point of attachment of the forewing to the apex.

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