414: PS 2"CHE. [November--December I89o. homology. It is utterly unphilospho- cal to accept without the clearest proof EXPLANATION TO BASE FIGURES. such a structural modification as this Fig. r. Si2blono2bkora avenae, a, beak change in position of the mandibles b, bristles ofmouth---"mandibles" and"max- would require, and the modification of illae;" c, antenna of winged viviparous the ordinary labium into a beak of this female. character is a process that ought to be Fig. 2. A2bhis brassicae, a, antenna of proven. It seems to be assumed that the wingless forms; b, antenna of winged vivi- "labium" of the hemiptera is the same parous female c, beak of young lice; d, beak of mature, winged form. as the "labium." of the diptera, e. g. Culex, and if this is so, I have a paper Fig. 3. Ahhis cucumeris, a, antenna of now in press, in which I claim to prove winged viviparous female; b, beak of wing- that this "labium" in the diptera is less forms. really only a modified galea, or a max- Fig. 4. Myzus cerasi, a, 3rd; b. 5th; illary structure. I hope to prove some c, 6th joint of antenna of winged viviparous time in the future, when I can get the female. necessary material, how this rnodifica- Fig. 5. AibMspersicae'nier" a, antenna tion of the hemipterous mouth came of immature forms, joints 5 and 6; b, 3rd; about, and that the mandibles do not, c, 4th; d, 5th; e, 6th joint of antenna of habitually, become internal mouth winged viviparous female; f, sensory pit from front;g; same from side. structures so long as there are other organs enough more naturally situated.

NOTES ON TWO SPECIES OF WITH DESCRIPTIONS OF THEIR LARVAL STAGES.

BY HARRISON G. DYAR, RHINEBECK, N. Y.

Of all the clogely related species of species differ, or rather tend to differ, this , the two which approach in other points beside the brightness of each other the most nearly and are most the costal shade, namely, in the more difficult to distinguish in the imago entire outer margin of the primaries, state, are D. rezajor and D. drexelii, and the darker more even coloration of I have elsewhere called attention to the the wings of D. major. main feature by which they are to be The size is the same in both species, distinguished, which, after all, is only there are no markedly distinctive male a matter of degree of coloration. The genital characters, and the lines and November--December 89o.] PS 1Ctt2. 415 spots are arranged in the same manner; predominance of yellow about the pro- in fact, there is no absolutely constant thoracic and the 8th, 9th and oth ab- difference, either in structure, markings dominal segments,* and this might serve or coloration, between the two so far as as an excellent protection, in that the I have been able to observe, and I have bunches of yellow striped larvae with no doubt that specimens may occasional- their extremities elevated in their cus- ly occur which it would not be possible tomary position, resemble the little to refer positively to one species or the clusters of flowers of the Witch-Hazel other by an examination of the imago with their linear yellow petals, which alone. It would at first seem that these begin to blossom in September, iust as species must be more closely related than the larvae become conspicuous. What others in the genus, perhaps hardly protection, if any, their coloration affords yet distinct; but when we consider the on the Deerberry, their other food-plant, larval stages, it is at once apparent that I am unable to say, as they occur ahnost they are widely separated, more widely, exclusively on the Witch-Hazel in this in fact, than many other species of .Data- vicinity. (Rhinebeck, N. Y.) na which are readily separable in the But as to D. major its curious spots imago state. This difference would seem do not resemble anything so far as I can to indicate rather a long inherited simi- see. It is to be noted, however, that larity between the than very recent the habits of the two species differ, for derivation from a colnmon ancestor. while D. drexelii are always gregarious, While the moths, it may be, have re- D. major, when they do not separate mained constant to their former type, entirely, feed farther apart, and tend to or undergone a similar development, the scatter more in the last stage than al- larvae have diverged greatly, which most any other species, and the change would seem to correspond to the gen- in ornamentation from lines to spots, eral rule in , that the larvae which they undergo in the last molt, are often the first to vary. The eggs of D. may be of use to them with their major and Z). drexelii differ markedly changed habits. the larval differences appear in the first ,. G. and are and stage kept up intensified 'ffg'. Sub-pyriform, of less diameter throughout the larval and period, only and cylindrical for a short distance at the when the is pupa stage reached, does top, recalling the structure of D. palmii; the close resemblance observed in the flattened at base or a little hollowed; moths begin. The cause of the diver- evenly flat on top with a sharp angle in the at gence larvae,especially maturity, between top and sides. Color uni- is not obvious, in the very particularly form sublustrous white, a rather peculiar ornamentation of D. major, which differs from that of all of the In this article, have followed the nomenclature other Dalana larvae so far known. used by Dr. Packard for the larval segments, as it is not possible to describe intelligently the markings nf D. drexelii is abnormal only in the .Dalana by the usual method. PSCHE. [November--December x89o. Spiracles velvety black. Hair white, days; and stage, 6 days; 3rd stage, 8 rather long, beside numerous fine, short days; 4th stage, 9 days. black hairs, all growing from minute FooD-eLaNT: Andromeda ligustri- black tubercles. Length of larva at maturity 60 mm. The form of this Larvae from Ulster Co., N. Y. larva with canary yellow bands and spots did not occur in any of the examples DATANA DREXEL'If, -[y..Edw. fl'om which these notes were made (a 2'gg. On the type of 29. ministra. brood of 55 and another large brood ob- Subcylindrical, of a little greater di- served in the field). I have formerly ameter near the bottom than near the found a few yellow ones among a brood top vertex rounded; base nearly flat. ofwhite spotted Z). major, and occasion- Color shiny whitish, the circular lid-like ally a brood entirely yellow. Though top very white and shiny, with a central the difference in coloration is very small round black spot. Diameter "7 marked between the two forms, it is ram. In hatching, the larva eats away evidently, from its mode of occurrence, the lid, and emerges from the hole thus only a variation. A similar variation formed. occurs in D. palmii* and less markedly First stage. Head rounded, black, in Z). contracta. shiny; width "5 ram. When newly l-uiba. Formed in a subterraneous cell. hatched, the larva is scarcely dis- In shape it is robust, cylindrical, thickest tinguishable from 29. major. The centrally, and rounded to the head cases anal feet are rather long and elevated. distinct; a slight creased elevation be- Body sordid yellow, cervical shield, anal tween the eyes. Abdominal segments plate and feet, blackish. A number of slightly tapering cremasters, two, very short hairs fiom the head and fiom short, not well separated, each with three about six rows of small blackish tuber- spines, the posterior one the longest, but cles which are larger in proportion than often two, or partly aborted. Cases in the subsequent stages. As the stage creased, body coarsely punctured, very advances, the body becomes reddish finely in the movable sutures. Color with four lateral stripes on each side dark or blackish mahogany. Length 25 and three ventral, about as wide as the mm., width 9 mm. This stage lasts intervening spaces, dull yellow and con- through the winter and the species is fluent posteriorly. During this stage, single brooded. The duration of the lar- the larvae eat the parenchyma in the val stages was as follows: st stage, same manner as 29. major. I have not observed, but probably about five estimated that a single larva eats about would like to call attention to the relationship 9 sq. ram. of Witch-Hazel leaf. that evidently exists between D. palmii and Z). major, Second stage. Head black and shiny They alike in egg structure, in the feature of bico. lorous larval hairs (which does not in any other with a few hairs, width t. ram. Body species to my knowledge), in coloration of heaa an.d brown, stripes dull yellow, narrower lines and in the slightly scalloped forewings of the . than the intervening spaces, extending November--December 89o. ISUCtIE 419 from the cervical shield and the anterior tured. Clypeus and labrum somewhat edge of the prothoracic segment to the wrinkled. Color shiy black, the an- anal plate and becoming a little con- tennae and palpi white-ringed, their bases fluent there. Cervical shield, anal greenish. Width 5'4 ram. Body black, plate, thoracic and anal feet and the cervical shield honey yellow, anal plate, abdominal feet outwardly black, tIir thoracic and anal feet and the abdomi- short and pale. During this stage, the nal feet outwardly, black. Anterior half larvae eat the whole leaf. of the prothoracic segment yellow; lird s/age, ttead higher than stripes narrower than the spaces, citron wide, depressed at the sutures of the yellow, running into the yellow part of clypeus; smooth shiny black, width the prothoracic segment and confluent .S mm. Body brown, the stripes yel- posteriorly on the tenth abdominal, low, confluent posteriorly and along the which is all yellow except the anal anterior edge of the prothoracic seg- plate and a dorsal band. The three ment. Otherwise as in the previous npper lateral lines are connected also o stage. the eighth and ninth abdominal seg- fi'oe.zr// stae,o'e. Head shaped as be- ments by a broad dark yellow shade. fore., smooth; centrally depressed at the The bases of the legs and corresponding top (f the clypeus anal more slightly spots on the apodous segments (on the along the central suture; clypeus and first, second, ad seventh, eighth and labrum wrinkled; all shining black ninth :bdoninal segcnts)also dark width 3.z ram. Cervical shield black yellow, forming expansions of the sub- or partly brow, in some examples ventral line and reaching the lowest nearly all light brown; anal plate, lateral lie, except on the thoracic seg- thoracic feet and the abdominal feet ments and the ninth aldominal. On outwardly, black. Body black or partly the apodous segments in the centre of brown, the anterior half of the pro- each yellow patch, is a small black spot. thoracic segment yellow, the stripes representing the absent legs, but this strongly confluent on the last segment. is not present in all examples. IIair The bases of the legs and corresponding rather abundant, sordid white, the long spots on the legless segments, as in the and short hairs cocolorous, arising from nature larva, of a darker yellow than lninute blackish tubercles which, in the the lines. Each segment is shaded cen- black parts of the body, are each sur- trally with this yellow, but it does not rounded by a minute yellow ring. cause the lines to appear confluent on liYa. Exactly like that of J). major; account of its darker shade. Hair sor- the two cremasters each bear three spines did white beside other short fine brown- in a transverse row, the posterior one i.sh hair seen with a lens. the longest. Length z8 ram;width o fi'ift/ stage. Head as high as wide, ram. flattened in front, depressed at the upper Single brooded, the winter being part of the sutures of the clypeus, punc- passed in the pupa state beneath the 420 PS YCHE. [November--December ,89o. ground. The duration of the larval days. stages was as follows.--st stage, 5 FOOD-PLANTS" Hamamelis Fir- days nd stage, 6 days 3rd stage, 6 ginica, Vacctziu,z stamineum. days, 4th stage, 7 days; 5th stage, 7 Larvae from Ulster Co., N. Y.

THE NUMBER OF MOLTS OF LEPIDOPTEROUS LARVAE.

BY HARRISON 13. DYAR RHINEBECK, N. Y. Two articles have already appeared in follows its own progression, we may PsycHF on this subject* and it is evi- conclude that this variation is actual; dent from a perusal of them that con- but if either set shows a lack of regular siderable confusion exists as to the progression that one we must regard number of molts of certain species, with suspicion. Corroborative observa- In this article I propose to establish a tions of the kind indicated are to be de- criterion by which different observa- sired and until we have them we can tions may be compared and errors de- not speak with confidence about the tected, for it is no difficult thing to number of molts of any species. overlook a molt or even to think one recommend that all who hereafter de- has occurred when it has not. scribe larval stages give the width of It will be seen by an examination of the head tbr each stage. I have selected the following figures that the widths of the head as the part not subject to the head of a larva in its successive growth during the stage, and its width stages follow a regular geometrical pro- as the most convenient measurement to gression, and if, in examining the meas- take. urements of heads taken in following In the following I give first the calcu- out a life history, any deviation from lated widths of head under each species, the calculated progression is shown, with the ratio, followed by those that it is evidence that an error has been were actually found. All measurements committed or that the larva has be- are in millimeters and may be con- haved in an abnormal manner; but the sidered accurate to within . mm. Cer- latter case can readily be distinguished tain irregularities are commented upon from the former if a moderate degree of in the notes to which the small num- care has been exercised in taking the bers refer. measurenents. Hence, if two sets of FOUR STAGES. observations show a different number of stages for the same but each Callosamia iSrometea Drury. calc. . .6 z. 3 3"3, r .7 W. H. [Edwards Psyche, 3, P. 59- A. K. Dimmock, Psyche, 5, P. z8. found .o .7 z'3 3"3 International Journal of Peptides

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