D. W. Farquhar.
Notes on a Psyehid New to North America (Fumea casta Pallas, Lepidoptera: Psychidæ).
Psyche 41:19-29, 1934.

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19341
A Psychid New to North America
NOTES ON A PSYCHID NEW TO NORTH AMERICA
(FUMEA CASTA PALLAS, Lepidoptera: Psychidse) BY DONALD W. FARQUHAR~
Harvard University
In 1931, workers from the Gipsy Moth Laboratory in Melrose Highlands, Massachusetts, found examples of an unknown case-bearer associated with the introduced beech scale, C~gptococcus fagi Bar., near Jamaica Pond, Boston, Massachusetts. Specimens of the case-bearer brought into the laboratory were observed to feed on the eggs and agamic females of the scale, but since this choice of food was decided to be purely incidental and the chief interest of the laboratory was in the scale rather than in the case- bearer, no further work on the latter was done. The writer, however, was interested in the identity of the insect and sent examples of the cases to Dr. Frank Morton Jones of Wil- mington, Delaware, who was unable to place them among any of the known North American forms and suggested that an attempt be made to secure adults. In 1932 two male adults were obtained, and in 1933 over 2,000 adults of both sexes were reared from larvae collected just prior to pupation; this ample material enabled careful study, result- ing in the determination of the insect as the European Fumea cmta Pallas. A discussion of the characters estab- lishing its identity is given in the paper which follows, while the present paper deals with the distribution and biology.
The writer wishes to express his deep appreciation to Frank Mor- ton Jones, specialist in the Psychidae, who has been most generous in giving of his time and knowledge. A paper which follows, and which bears the name of the writer of the present paper as coauthor, is al- most entirely Dr. Jones' own work.
Thanks are also given to Harold Morrison, C. F. W. Muesebeck, A. B. Gahan, and R. A. Cushman, all of the taxonomic unit of the Bureau of Entomology, who examined parasitic material and made determinations where possible.
Pu&e 41:19-28 (1934). hup ttpsychu einclub org/41/41-019 html



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20 Psyche [March
In the Old World, Fumea casta Pall. is widely distributed in England, on the European mainland, in Asia Minor and Algeria. The first specimens discovered in North America were found between Jamaica Pond and the Arnold Arbore- tum, in Boston, Massachusetts; and subsequent scouting showed this region to be near the center of an area of some 50 square miles (Fig. I), heavily infested at the center, and FIG. 1.
Map showing regions in Boston and vicinity infested with Fumea casta Pall.
gradually diminishing in density toward the edges. Ap-
proximately half of the area comprised those sections within the limits of the City of Boston known as Jamaica Plain, Forest Hills, Roslindale, West Roxbury, Hyde Park, Mattapan, the Arnold Arboretum, Stoney Brook Reserva- tion, and Franklin Park; the remaining 25 square miles were in Brookline, Newton Highlands, Dedham, Milton, and the Blue Hills Reservation. A second, and far removed, colony was later found by Dr. Jones in the Morris Arbore-



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19341 A Psychid New to North America 21
turn, near Germantown, Pennsylvania ; females from this colony readily mated with Massachusetts males; many of the older plantings in the Morris Arboretum are said to have originated in the Arnold Arboretum, which may ex- plain the mode of introduction. A third colony is indicated by empty cases, apparently identical with those of Fumea, found by Dr. W. T. M. Forbes in Bancroft Woods, in Wor- cester, Massachusetts.
Other colonies are to be anticipated.
Larva and Case. The larvae hatch during June and early July, and at once each individual constructs a small silken case, or "bag," in which, enlarged from time to time, it spends its entire larval and pupal period. This elongate bag is adorned on the outside with bits of grass and other ground debris, longer pieces being attached lengthwise and often projecting slightly beyond the posterior end of the bag. Through an anterior opening, the larva is able to thrust out its head and thorax for purposes of feeding, moving, or working on the case; the posterior end of the case has a smaller opening, usually collapsed but readily opened from within for the expulsion of excrement. During resting and molting periods the anterior edge of the bag is firmly at- tached by silken threads to some object of support. Food is taken only during the larval period, and consists chiefly of grasses, mosses, lichens, and other low plants, al- though the insect may occasionally exhibit carnivorous tendencies, as evidenced by feeding on scale insects and, in the laboratory when very hungry, on the living larvae and helpless adult females of its own species. As in many other members of this family, the larval pe- riod is very protracted (Fig. 2) -occupying approximately eleven months-and growth is correspondingly slow. From the time of hatching in June or July until the onset of win- ter, the larval case attains a length of but three millime- ters. Hibernation takes place in crevices in the bark of tree trunks, or beneath stones, branches of trees, and other objects resting on the ground. In the spring, feeding is re- sumed, and growth is more rapid. When the larvae are ma- ture, in late May and early June, the cases of the females are generally larger than those of the males. Measurements of fifty female cases at this time, inclusive of the loose ma-



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22 Psyche [March
terial projecting beyond the end of the case proper, showed a range in length from 8 to 16 mm., with an average of 12.1 mm.; measurements of the same cases, exclusive of the loose material, ranged from 7.5 to 10 mm. with an average of 8.8 mm. Fifty male cases ranged from 7.5 to 13.5 mm., with an average of 10.2 mm., inclusive of the loose material ; when measured without the loose material, these male cases ran from 6.5 to 8 mm., with an average length of 7.5 mm. FIG. 2.
Life cycle of Fumea casta Pall. in Massachusetts. When the larvae become full grown, they forsake the ground and low plants on which they have spent their en- tire lives up to this point, and climb up tree trunks, tele- graph poles, fence posts, stone walls, sides of dwellings, etc., to attach their cases for pupation. The height to which the larva ascends before attaching the case varies from-a few inches to twenty feet, but few are attached above six feet. Although the larvae on the ground easily escape notice even in densely populated colonies because of



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19341 A Psychid New to North America 23
the close resemblance of their cases to the surroundings, the cases attached for pupation are conspicuous and often ren- der unsightly the objects of attachment. Pupa. Like the larval period, the pupal period is passed within the bag. After firmly attaching the bag and closing its anterior end in preparation for pupation, the larva re- verses its position within the bag so that its head comes to lie at what was previously the bag's posterior opening. Rarely, the larva fails to reverse its position, but in such instances the adult is unable to escape from the bag and perishes within it.
The pupae of the two sexes are quite different in appear- ance. That of the male measures from 4.5 to 5 mm. in length, and has the general appearance of orthodox moth pupae. That of the female measures 5.3 to 7.5 mm. in length, and is noteworthy because of the marked reduction in size of the antennae, wings, and legs, all of which occupy a very limited area of the anteroinferior portion of the Pupa*
In both sexes, when the pupa is ready to yield the imago, it squirms forward in the bag until the head of the pupa projects from the bag's opening; in the male this squirm- ing continues beyond the stopping place in the female, until not only the head projects, but also the thorax and three to five segments of the abdomen. In this position the adult emerges.
The duration of the pupal period is about twelve days in the male, and about seven days in the female. Adult Male. (Plate 2, figs. C and F.)
The male moth is
uniformly dark brown in color, and is provided with strong wings to which the scales are loosely attached. The alar expanse varies from 10.5 to 13 mm. (Chapman and Tutt give measurements of 9-15 mm. for European casta.) No food is taken by the adult, and the duration of life is but a very few days at most.
Adult Female.
(Plate 2, figs. A and B.) In the higher
Psychidse, to which all the North American Psychids be- long with the exception of Solenobia wcdshella Clem., the females are maggot-like and devoid of antennae, eyes, and legs. In the lower or less specialized Psychidse, the females



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are provided with functional legs, antennae, and eyes. In
this latter group belong the native Solenobia walshella and the introduced Fumea casta. The female is wingless, and the body is practically naked save for a thin scattering of pale hairs and a dense ring of pale, silky hairs at the end of the abdomen surrounding the base of the long, extensible ovipositor. After the female casta has feebly squirmed her way out of the pupa-shell, she takes up her waiting posture at the lower end of the bag, still maintaining contact with the interior of the bag by means of her metathoracic legs; often her head, antennae, and prothoracic legs remain en- cased in the corresponding parts of the pupa-shell which are broken away from the rest of the shell during emer- gence. Like the adult male, the adult female takes no food, and her life in this stage is limited to a very few days. Mating. Immediately after emerging, the female liber- ates the attractant which summons males within perceiving distance. A male receiving this attractant evidences its perception by becoming suddenly very much excited. He takes flight and follows an erratic course in the direction of the female. Seldom is the sense of perception sufficiently keen to enable a flight direct to the object of search; the usual course is to fly to the general vicinity of the female, then after alighting, with vibrating antennae and quivering wings, the male continues his quest on foot. His excitement increases in pitch when he attains the bag on which his mate is waiting, and he usually makes several impetuous attempts to clasp nearby objects before making successful contact with the female genitalia. The commencement of copulation is indicated by the male suddenly becoming qui- escent, resting with the wings sloped sharply downward (in a "sloping-roof" posture). Seven timed matings indicate a copulation period of six to thirty-eight minutes, with an average of 20.4 minutes. Both sexes may mate more than once, although such successive matings in the female usu- ally occur only when the original mating has been inter- rupted before completion.
Eggs. As soon as mating is completed, the female probes with her ovipositor to reinsert it in her empty pupa-shell, which lies within the bag; in this process of probing she is



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19341 A Psychid New to North America 25
assisted by the metathoracic legs, the tibia and tarsus of which are still within her bag, and probably facilitate the reinsertion of the ovipositor by acting as a guide. The eggs are pale in color and very delicate, and are deposited by means of the extremely manceuverable, telescopic ovipos- itor, which, when fully extended, equals the length of the remainder of the female's body. When the last of her 150- odd eggs have been deposited, the female withdraws her ovipositor, closing the opening to her egg-filled pupa-shell with a plug of fuzz from the tip of her abdomen; she then relinquishes her hold on the bag, and drops to the ground to die. The eggs hatch in thirteen to fifteen days, the young larvae leaving the parental bag via its open end. Dispersal.
Since the adult female is incapable of flight or other locomotion, the dispersal of the species depends on the wanderings of the larvae, and especially their transpor- tation by other agencies. Just as human beings have un- wittingly brought this insect to America, so, too, its dis- persal within America is probably greatly assisted by man's conveyances. Another factor in the dispersal is the wind; as soon as the newly hatched larvae have constructed their tiny cases, they have the habit of dropping themselves down on a silken thread, in which condition they are easily picked up by wind currents to be droppled perhaps at some dis- tance away. Since evidence indicates a sojourn of the in- sect in this country of at least two decades, with these vari- ous factors aiding in its distribution, the insect probably will soon be found in many, and possibly widely separated localities.
Parthenogenesis and Preponderance of One Sex. Al-
though parthenogenesis has been recorded in the genus Fu- mea in Europe-and, indeed, has been reported in Fumea casta (Fauna Boica 11, 91, Schrank)-no evidence of this phenomenon has been observed in Massachusetts casta. Fifteen unmated females from the Boston colony were iso- lated in an experiment designed to detect evidences of par- thenogenesis. All died without ovipositing, within five days after emergence.
In both Europe and America, authors have remarked upon the occasional striking preponderance of one sex over



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26 Psyche [March
the other in Psychid rearings. In parthenogenetic species, females are either the only form known or greatly outnum- ber the males. In America, Dr. Jones has mentioned (Tr. Am. Ent. Soc., LIII, 310, 1927) a collection of thirty-odd cases of Ewukuttarus edwardsi Heyl. of which only one was female; the same author (Ent. News, XXXIII, 130. 1922) bred some forty males without a single female from a collection of Psyche celibata Jones. Returning to Fumea casta, a similar numerical ration between the sexes was found in many of the Massachusetts collections, as shown in the following table based on adults bred from cases col- lected at time of pupation; where cases failed to yield adults, they were opened and the sex determined from the enclosed pupae; in those few cases where the larvae died, accurate sex determination was not considered possible, and such individuals are ignored in the tabulation : TABLE 1.-Sex ratio in certain collections of Fumea casta in Massachusetts.
Date of Number of
collection Place of collection individuals % 8 8 % Q Q May 6, '33
May 6, '33
May 12, '33
May 13, '33
May 22, '33
May 22, '33
May 22, '33
June 5, '33
Arnold Arboretum ................ 7
Stoney Brook .......................... 70 Stoney Brook .......................... 69 Arnold Arboretum ................ 100
Arnold Arboretum ................ 130
Fenway .................................... 25 Jamaica Pond ........................ 100 Jamaica Pond ........................ 375 Interpretation of the above table is complicated by *the fact that the Jamaica Pond colony was some two weeks be- hind the other colonies in reaching maturity; in fact, for a time the larvae of this colony were considered as possibly of another species because of their smaller size. Therefore,
the high percentage of females in the latest collection does not necessarily mean that similar results would have ob- tained if later collections had been made at the other sites. It appears from the table that the earliest larvae to pupate are the males, which conforms with the condition in many other Lepidoptera. The striking preponderance of males



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Psyche, 1934
VOL 4, PLATE II.




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19341 A Psychid New to North America 29
may be due to some peculiar habit of the female in choos- ing different or more concealed places for pupation than the males, thus rendering their cases less liable to detection by the collector.
Parasites.
Apparently Furnea casta has become estab- lished in America without its European parasites. Al- though the writer reared over 2,000 adult moths from cases collected at the time of attachment, only eleven parasites emerged from the material, and probably all eleven of these emerged from a single host. They proved to be a new spe- cies and genus of Eulophidse related to Elachertus, as yet undescribed. Several hundred cases collected in Massachu- setts were sent to Dr. Jones, and from them he reared eleven specimens of Dibrachys boucheanus (Ratz.) [A. B. Gahan]. Dr. Jones also reared two specimens of Itoplectis conquisitor (Say) [R. A. Cushman] from cases collected in the Morris Arboretum in Pennsylvania.
In addition to these definite instances of parasitism, two species were found in the field associated with Fumea casta: A female of Ephialtes equalis (Prov.) [R. A. Cush- man] was taken in the field with its ovipositor thrust through a bag attempting to oviposit in the contained pupa. A specimen of Eunotus lividus Ash. [A. B. Gahan] was found in a tube in which cases of casta were being collected, and probably gained entrance to the tube by being on or within one of the cases when it was collected. Fig. A.-Adult females on their bags (x2). Fig. B.-Adult females (x2).
Fig. C.-Adult males (x2Y9).
Fig. D.-Bags from which adult males have emerged leav- ing their empty pupa-shells protruding from the bags (x2Y2) .
Fig. E.-Bags attached for pupation on a stone wall in a heavy infestation ($$ natural size).
Fig. F.-Adult males (~3%).




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