Llewellyn Jones, J. R. J.

English

Journal of the Entomological Society of British Columbia

6 E:'ITO~lOLOGICAL Soc. OF BRITISH COLl;~IBIA. Pnoc. (1948)' VOL. 45, JULY 28, 1949 AN EXPERIMENT WITH LARVAE OF LAMBDINA FISCELLARIA SOMNIARIA HULST J. R. J. LLEWELLYN JONES Cobble Hill, B.C. As long ago as 1905 it was recognized that there was a close connection between the oak looper, then known as Therina somniaria Hulst, and the hemlock looper, Therina fiscellaria Guenee. In the Bulletin of the British Colum-bia Entomological Society, 1906, No.3, September, page 3, in an article entitled ccTherina somniaria at Victoria," Dr. J. Fletcher is quoted as saying that, during an outbreak the previous year, larvae of somniaria were observed feeding on west-ern hemlock, spruce and Douglas fir. Also the Rev. G. W. Taylor is reported as con-sidering somniaria Hulst, to be a variety of fiscellaria Guenee. More recently a paper has been pub-lished by H. W. Capps entitled "Some American Geometrid moths of the sub-family Ennominae heretofore associated with or closely related to Ellopia Treit-schke" (Proc. United States Museum, 93 (3159):115-150, Washington, 1943) in which the writer regards somniaria Hlst., as a regional race of fiscellaria Guenee and places them in a new genus Lamb-dina Capps. H e states that examination of the genitalia confirms his arrangement. The oak looper therefore becomes Lamh-dina fiscellaria somniaria Hlst., and the western hemlock looper Lambdina fircd-Laria lugubrosa Hlst. In support of this view, I submit the following notes on an experiment carried out last season with larvae of somniaria, obtained during a severe but local out-break in the Saanich District of Victoria on Garry oak, Quercus garry ana Douglas. Eleven hundred larvae were obtained in varying stages of growth. Of these two hundred were placed in a container and fed with western hemlock, Tsuga he-terophyLla Sargent. The larvae readily accepted this and fed to maturity. Sixty-three imagines were obtained during Sep-tl~mber and Octoher, a percentage of 31.5. Of the remaining 900, which were allow-ed to continue feeding on G arry oak, 473 imagines were obtained, a percentage of 52.5. Both groups of insects showed the same range of colour variation, but there was an appreciable difference in the size of the imagines. Those which had been giv-en hemlock were smaller and more close the normal size of fisccllaria lugubrosa HIst. A verage measurements were as follows: 1. Fed on oak 1. 7 5 inches. 2. Fed on hemlock 1.50 inches. The converse experiment was not so successful due chiefly to the lack of heal-thy specimens. Some 70 larvae of the hemlock looper, L. fiscellaria Lugubrosa Hlst., were received from Mr. G. R. Wyatt, early in August from th e Sarita Ril'er area on Vancouve r Island. They were heavily parasitized and also were suf-fering from a virus in fection, consequent-ly mortality was great. Only one imago was obtained, a rather small sized male. The larvae survived long enongh how-ever to satisfy me that they would readily accept nak as a food plant. About 20 lar-vae were supplied with oak, which they promptly ate. In conclusion, it would seem reasonable and, I deem, desirable, to accept H. W. Capps' re-arrangement of this group, about which, in the past, there has been some disagreement and speculation. 

An experiment with larvae of Lambdina fiscellaria somniaria Hulst

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An experiment with larvae of Lambdina fiscellaria somniaria Hulst

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Journal of the Entomological Society of British Columbia