VOLUME 24, NUMBER 2 151 MACY, R. W., AND H. H. SHEPARD. 1941. Butterflies. Minneapolis. MASTERS, J. H., AND W. L. MASTERS. 1969. An annotated list of the butterflies of Perry County and a contribution to the knowledge of Lepidoptera in Indiana. The Mid-Continent Lepidoptera Series, No.6. MATHER, B., AND K. MATHER. 1958. The butterflies of Mississippi. Tulane Stud. Zool. 6: 63-109. MOOHE, S. 1960. A revised annotated list of the butterflies of Michigan. Occasional Papers of the Museum of Zoology, UniverSity of Michigan, 617: 1-39. RANDOLPH, V. 1929. A calendar of Kansas butterflies. Ent. News 40:88-92. RICHAHDS, A. G., JR. 1932. Distributional studies in southeastern Rhopalocera. Bull. Brooklyn Ent. Soc. 26: 234-255. Hoss, C. N., AND E. N. LAMBREMONT. 1963. An annotated supplement to the state list of Louisiana butterflies and skippers. Jour. Lepid. Soc. 17: 148-158. SKINNER, H. 1897. A new species of Debis. Ent. News 8: 236. --~ 1926. Enodia portlandia, andromacha and creola (Lep., Rhopalocera). Ent. l\;ews 37: 42-43. STRECKEH, H. 1878. Butterflies and moths of North America. Reading, Pa. THE LIFE HISTORY OF EUTRlCOPIS NEXILIS ( NOCTUIDAE ) D. F. HARDWICK Entomology Research Institute, Canada Departmcnt of Agriculture, Ottawa, Onto Eutricopis nexilis Morrison (1875, p. 102) feeds in the larval stage on the heads of species of Antennaria, a complex genus of the Compositae, that is widespread in temperate North America. The insect itself is also widespread. In Canada, it is distributed from Nova Scotia to southcentral Ontario, and from southern Saskatchewan to southern British Columbia. There is an apparent hiatus in its distribution through western Ontario and southern Manitoba. In western North America, the species is distributed southward at least as far as Colorado. In western Quebec, nexilis flies during May; with increasing elevation in the west, however, the period of adult activity is progressively retarded, and at an altitudc of 6,000 feet in southern British Columbia, the flight period may be protracted into the first part of August. Eastern and western populations differ in both adult and larval characteristics. Eastern adults are distinguished from western adults by a less patchy appearance of the dark areas of the forewing and by a reduction in the extent of the white areas on both fore- and hind wings. Moreover, representatives of eastern populations are significantly smaller at the one percent level than their western counterparts, the mean expanse for eastern material being 16.2 ± 1.1 mm l (24 specimens) in 1 Standard deviation
152 JOURNAL OF THE LEPIDOPTERISTS' SOCIETY contrast to 18.5 ± 1.1 mm (60 specimens) for western material. The larvae of eastern specimens are similarly smaller than western larvae, and most noticeably so in the last stadium. The time required for larvae to complete their growth is also significantly shorter among eastern individuals than among western individuals. The mean duration of the feeding phase of the larval stage of specimens reared from Hull, Quebec was 15.0 ± 0.9 days (18 larvae) and from Keremeos, E.c. 21.3 ± 2.9 days ( 12 larvae). The two are significantly different at the one percent level. On the basis of differences in both larvae and adults, eastern and western populations of Eutricopis nexilis might be considered as representing different subspecies. Behaviour Eutricopis nexilis is an exclusively day-flying species, and has the greatly reduced compound eyes that are commonly associated with this period of activity. The little moth flies very quickly and the patchy dark and white pattern of both fore- and hind-wings makes it almost impossible to keep the insect in view. In the cooler parts of the day and during cloudy periods, adults of the species commonly rest on the flowering heads of the food plant. The eggs are deposited singly among the florets of Antennaria, the female forcing her abdomen down through the head from the top to oviposit above the dcveloping seeds. For a noctuid moth of such small size, E. nexilis deposits an extraordinarily large egg. The pattern of depositing such a large egg is one that has evidently developed within some of the smallest heliothidine moths to insure the survival of their progeny (for discussion, see Hardwick 1969). The fecundity is correspondingly low; five wild-caught females, taken at Hull, Quebec, deposited a mean of 7.8 eggs, and the maximum laid by any individual female was ten. A majority of the eggs observed, hatched on the fourth day after deposition. The newly hatched larva feeds first on the florets, then on the developing seeds. First- and second-stadium larvae show very characteristic external evidence of their feeding within a head. One to several florets are severed at their junctures with the seeds and the florets are pushed outward so that they protrude above the general surface of the head. Usually during the third stadium, the larva quits the first head and enters a second, making its way downward through the top of the head toward the seeds. Third- and fourth-stadium larvae also give typical external evidence of their presence within a head. All of the florets are severed from the
VOLUME 24, NUMBER 2 153 Figs. 1, 2. Etttricopis nexilis Morr. 1, Nickel Plate, Hedley, B.C., 6,500 feet; 2, Mt. St. Hilaire, Que. seeds and pushed outward and a tangled mass of florets and pappi are left protruding from the receptacle (Fig. 3). The mass does not seem to become dislodged from the plant, however, and it may be secured into position by strands of silk. The larger larva thus fashions a nest for itself within the receptacle so that it may remain concealcd while feeding on the seeds. Larvae mature in four stadia. At the cessation of feeding, the larva makes its way to the ground and fashions an elongate cocoon or pupal cell whose walls are formed of granules of soil and bits of organic debris (Fig. 8). The pupal cell is formed at or immediately below the surface of the ground. In one case observed, the larva on ceasing to feed, actually formed a pupal cell among the heads of its food plant (Fig. 4). So far as is known, Eut-ricopis nexilis is entirely single-brooded throughout its range. It overwinters as a pupa in the earthen cell at the surface of the ground. Descriptions of Stages Data on the immature stages of Eutricopis nexilis are based on rearings from three localities: Aylmer, Quebec; Twin Lakes, Keremeos, B.C., 4,700 feet; and Osoyoos, B.C., 4,000 feet. The durations of stadia listed are those obtained from rearings maintained at room temperature. Rearing techniques employed were the same as those outlined by Hardwick (1958). The estimate of variation, following the means for various measurements, is the standard deviation. Adult (Figs. 1, 2). Vestiture of body consisting of black, closely appressed scales overlaid by elongate, yellowish-grey or olive-grey, hair-like vestiture; overlying vcstiture of abdomen usually not heavy. Forewing olive-grey, marked witb pale yellow or white and suffused with red. Basal space broad, extending outward to incorporate all of orbicular spot; usually a narrow, pale-yellow or wbite triangle in anterior region of basal space marking the proximal margin of orbicular; basal space variably overlaid and suffused with dark red, most strongly so anteriorly and outwardly; red suffusion occasionally so extensive as to obscure any olive-grey colouring.
154 JOURNAL OF THE LEPIDOPTERISTS' SOCIETY,, T Figs. 3-8. Eutricopis nex'ilis Morr., immature stages and damage. 3, Tufting of florets of Antennaria sp. caused by larval feeding; 4, an unusual cocoon fonned in the head of Antennaria sp.; 5, dorsal aspect of fourth-stadium larvae; 6, right lateral aspect of fourth-stadium larvae; 7, pupae; 8, pupal cell. Median space pale yellow or white, very narrow because of enlargement of basal space; anterior half of median space containing a large, dark, usually rectangular, reniform spot; pale central area of median space often separated from margins of wing by a dark band along costal margin and another along trailing margin. Transverse posterior line usually smoothly biarcuate. Subterminal line irregular, marked only by colour change between subterminal and terminal spaces. Subterminal space shades of red or reddish-brown, rarely olive. Terminal space olive-grey. Fringe usually white or pale grey, occasionally concolorous with terminal space. Hind wing dark blackish-brown with two white central spots; central spots often coalescing to form an irregular white central band. Fringe white. Unde1 side of forewing with a pink or brown basal space in which orbicular and daviform spots often well defined. A white median band containing a large, dark-brown dis cal spot. A broad dark-
VOLUME 24, NUMBER 2 155 Figs. 9, 10. Apical abdominal segmcnts of pupa. 9, Ventral; 10, left lateral. brown, outer-marginal band extending forward from outer angle almost to apex. A white patch, margined proximally with pink, at apex of wing. Fringe brown at apex, otherwise white. Underside of hind wing with a brown patch at anal angle and a brown suffusion along inner margin. Anterior half of wing white or pale grey variably suffused with pink. Two white central spots or an irregular central band. Fringe white with a brown basal line. Expanse: Eastern populations, 16.2 ± 1.1 mm (24 specimens); western populations, 18.5 ± 1.1 mm (60 specimens). Egg. Very pale greenish-yellow when deposited; darkening gradually in the next three days first to a dark yellow and then to a dull orange. Micropylar half of egg becoming brown on the third day after deposition. Entire outline of larva vrsible through chorion within a few hours prior to hatching. Dimensions of egg: 0.854 ± 0.019 mm X 0.539 ± 0.019 mm (3 eggs). Incuhation period: 4.4 ± 1.0 days (25 eggs). First Stadium Larva. Head black. ProthOl'acic and suranal shield medium to dark grey. Trunk pale translucent yellow, often with a strong internal orange suffusion. Head width: Keremeos, B.C., 0.361 ± 0.013 mm (9 larvae); Hull, Que., 0.353 ± 0.014 mm (16 larvae). Duration of stadium: Keremeos, B.C., 3.2 ± 1.8 days (12 larvae); Hull, Que., 3.9 ± 0.8 days (18 larvae). Second-Stadium Lana. Head black. Prothoracic and suranal shields dark brown. Trunk varying from ashen grey to yellowish grey. Setal bases, thoracic legs and rims of spiracles dark brown. Head width: Keremeos, B.C., 0.568 ± 0.025 mm (26 larvae); Hull, Que., 0.557 ± 0.022 mm (16 larvae). Duration of stadium: Keremeos, B.C.,.3.8 ± 0.6 days (12 larvae); Hull, Que., 2.2 ± 0.6 days (18 larvae). Third-Stadium Larva. Head light to m edium brown, variably suffused and mottled with dark brown; dark suffusion often so prevalent as to obscure any paler colouring. Protboracic and suranal shields usually paler than head, brown, mottled with darker brown; prothoracic shield usually with one or two pairs of pale longitudinal lines. Trunk light to medium grey, usually with a strong greenish tone; a
156 JOUHNAL OF THE LEPIDOPTERISTS' SOCIETY middorsal and a pair of subdorsal brownish longitudinal bands often evident. Rims of spiracles brown. Proleg shields concolorous with trunk. Setal bases and thoracic legs medium to dark brown. Head width: Keremeos, B.C., 0.924 ± 0.037 mm (25 larvae); Hull, Que., 0.846 ± 0.051 mm (IS larvae). Duration of stadium: Keremeos, B.C., 4.7 ± 1.0 days (12 larvae); Hull, Que., 3.4 ± 0.8 days (18 larvae). F'ourth Stadium Larva (Figs. 5, 6). Head pale yellowish-fawn or greenishfawn, variably mottled and suffused with chocolate-brown dorsally and in centre of face; head often only weakly marked with brown. Prothoracic shield fawn marked with dark brown, usually more heavily marked than head; with a pale-yellow middorsal line and a pair of paler-yellow sublateral bands. Suranal shield fawn marked with black. Middorsal band varying from reddish-brown to purplish-red. Subdorsal area consisting of a dark median band and palc marginal lines, the dorsal marginal line colllmonly evanescing; median band of subdorsal area varying from a reddishbrown, paler than that of middorsal band, to a medium green with a faint pink suffusion. Supraspiracular area similar in color to median band of subdorsal area; with an irregular and discontinuous, pale greenish-yellow median line passing through it. Spiracular band greenish-grey, poorly distinguished from suprapodal area. Suprapodal and midventral areas concolorous, varying from greyish-green to apple green. Proleg shields concolorous with suprapodal area. Setal bases and rims of spiracles dark blackish-brown. Thoracic legs medium brown. Head width: Keremeos, B.C., 1.482 ± 0.073 mm (12 larvae); Hull, Que., 1.354 ± 0.076 mm (25 larvae). Dmation of feeding phase of fourth stadium: Keremeos, B.C., 9.7 ± 2.6 days (12 larvae); Hull, Que., 5.4 ± 1.2 days (18 larvae). Duration of pl'epupal phase of fourth stadium: Keremeos, B.C., 6.2 ± 3.2 days (9 larvae); Hull, Que., 4.7 ± 0.7 days (12 larvae). Pupa (Figs. 7, 9, 10). Uniform light yellowish-brown. Rims of spiracles on a level with general surface of cuticle. Anterior marginal areas of abdominal segments 5, 6 and 7 o~ly weakly pitted. Apex of wing extending posterior to apex of proboscis. Apex of tenth abdominal segment dorsoventrally flattened and with a truncated posterior margin; with a pair of conspicuous, short, stout setae on either side; an additional, smaller, lateral seta anterior to the conspicuous pair; also a pair of subapical dorsal setae. Length to posterior margin of fourth abdominal segment: Keremeos, B.C., 4.81 ± 0.60 mm (16 pupae); Hull, Que., 4.05 ± 0.32 mm (4 pupae). Acknowledgments I am grateful to Mr. John E. H. Martin of this Institute for assistance in the field and for the fine photographs accompanying this paper. I appreciate the assistance of my associate, Mr. E. W. Rockbume who measured the immature stages and drew the cremaster area of the pupa. Literature Cited HARDWICK, D. F., 1958. Taxonomy, life history and habits of the elliptoiel-eyed species of Schinia (Lepidoptera: Noctuidac) with notes on the Heliothidinae. Can. Ent. Suppl. 6, 116 pp. 1969. The life history of Heliolollche carolus (Noctuidae). J. Lepicl. Soc. 23: 26-30. MORRISON, H. K. 1875. Notes on North American Lepidoptera. Ann. Lyceum Nat. Hist. N.Y. 11: 91-104.