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Volume 30, Number 2
137
Acknowledgment The drawings were prepared by Mrs. Lily Shen.
Literature Cited
Heinrich, C. 1956. American moths of the subfamily Phycitinae. U. S. Nat. Mus.
Bull. 207. 581 p. MacKay, M. R. 1972. Larval sketches of some Microlepidoptera, chiefly North
American. Mem. Ent. Soc. Canada 88. 83 p. Ragonot, E. L. 1887. Diagnoses of North American Phycitidae and Galleriidae.
Paris. 20 p. Ragonot, E. L. & G. F. Hampson. 1901. Monographic des Phycitinae et des
Galleriinae II. In Mem. sur les Lepidopteres. 8. St. Petersburg. 602 p. Roesler, R. U. 1973. Phycitinae. Parts 1 and 2. In Microlepidoptera Palaearctica.
4. Vienna. 752 p. & 137 p.
SUMMER MONARCH (DANAUS PLEX1PPUS) IN SOUTHERN TEXAS
(DANAIDAE)
The monarch, Danaus plexippus (L.), is by far the best-known butterfly in North America. During several years' personal observation in the Brownsville, Cameron Co. area of southern Texas, monarchs were normally observed only from late September through April. Adults were most commonly seen in the fall and early spring as they migrated south and north, respectively. However, in warmer years monarchs were observed during the winter months. Other observers (see Urquhart 1960, The Monarch Butterfly, U. Toronto Press, pp. 165, 172-173; Yeager 1974, News Lep. Soc. 1974(3), p. 3) have reported similar near total absences of monarchs in southern Texas during summer months. Summer breeding of monarchs is normally limited to northern Texas and areas to the north.
However, in June and July 1966 larvae of the monarch were found in Brownsville on milkweed. Adult monarchs reared from wild larvae in the laboratory emerged on 17 June (2), 19 June (4), 3 July (1), 5 July (1) and 11 July (2). Climatic factors could have been involved in this southern extension of summer breeding of the monarch in 1966. Temperatures during January-May were cooler than normal. January was wetter than normal followed by three months of very little rainfall (2.16 in.) until a very wet May (6.05 in. vs. normal 2.50).
Another possible factor needs to be considered. The monarch butterfly is subject to cyclical population crashes which have attributed to a cytoplasmic polyhedrosis virus (Urquhart 1970, Atalanta 3(2): 1-11). The year 1966 was characterized by generally low populations throughout most of North America, including southern Texas (Urquhart 1970, op. cit.). If the monarch is less prone to migrate during low population periods as suggested by Urquhart (1970, op. cit.), this aberrant summer occurrence of the monarch in the Brownsville area may have been the indirect result of a virus outbreak.
Raymond W. Neck, Texas Parks and Wildlife Department, John H. Reagan Building, Austin, Texas, 78701.