A Collection of Birds from Omilteme, Guerrero

192 GRmCOM,Birdsfrom Omilteme, Guerrero LApril[Auk

A COLLECTION OF BIRDS FROM OMILTEME, GUERRERO

BY LUDLOW GRISCOM

Ix THEspring of 1936, Mr. W. W. Brown, Jr., returnedto the State of Guerrero,Mexico, and with Mrs. Brown succeededin perfectingarrange- mentsto campfor sometime in the high rain forestat Omilteme,a place famousas the type locality of many endemicspecialties of the high Sierra Madre del Sur. Work was begun on March 20 and continuedthrough July 8. While Omiltemewas 'headquarters'throughout this period, other localitiesappear on Mr. Brown'slabels as follows: Mujileca (April 16 only), Esposcalete(April 30 only), Isguagilite (May 13-20), Rincon Caparosa (May 24 only), Jaleaca(June 6 only). Three of theseplaces are hamletson the mule trail from Chilpanclngoto Omilteme. The othersmust be in the immediatevicinity, as birds were shot at Omiltemeon the sameday. All are slightly lower in altitude. None is of the slightestreal consequence, except Isguagilite,where the fair number of birds collectedshows a high percentageof speciescharacteristic of the TropicalZone with almostno Subtropical-Zoneforms. The collectioncontains 490 specimens,belonging to 107 species,and is consequentlyvery criticallyselected. With very few exceptions,the only speciesin seriesare the speciallydesirable birds of higheraltitudes, all of which were breeding,as definitely proved by careful dissection. It is interestingto note that fifteen speciesout of 107 are new to Guerrero. The resultsappear to justify my predictionof the numerousprobable additionsto the avlfauna of Guerrerowith further collecting(cf. Grlscom, 'Ornithologyof Guerrero,'Bull. Mus. Comp. Zo51.,vol. 75, pp. 367-422, January, 1934). This report is purely supplementaryto that paper. All speciescommon or alreadywell knownin Guerrero,are not listedand com- ment is confinedto strictly new or interestingmatter. Penelope purpurascenspurpurascens Wagler.--1 •, Omilteme. A little-known bird in western Mexico, here at an unusually high aJtitude. Dendrorty:rmacroura striatus Nelson.--3 •, 2 •, Omilteme. A fine series of one of the rarest partridgesin the New World. Only two specimensare definitely re- corded:Nelson's type and a specimen,collected by Mrs. H. H. Smith, in the British Museum. There is no doubt but what we have in this seriesa subspeciesstrikingly distinct from typical macroura. It is much smaJler,with a radically shorter tarsus and generallydarker colorationthroughout. This last is most noticeableon the underparts,which entirely lack the whitish ground color seenon the lower breast and abdomen of macroura. Nelson's claim that striatus differs in having the sides and flanks more heavily streaked with chestnut proves to be without foundation. It should be noted that both griseipectusNelson and oaxacaeNelson have page priorityover striatus Nelson, and comefrom closelyadjacent areas. Goodseries of Vol.1037 J GRISCOM,Birds from Omilteme, Guerrero 193 thesetwo formsare alsobadly needed before it canfinally be settledjust howmany valid subspeciesthere may be. Cyrtonyxsallei J. Verreaux.--1•, Isguagilite,May 17, 1936. This rare OceIlated Quailis knownfrom a merehandful of males;the onlydefinite locality on recordis Amula in Guerrero. The female has hitherto been unknown. The male is nearer to montezumaethan to ocellatusin characters.Grant, in the 'Catalogueof Birdsin the British Museum,'supposed that the femalewould resemble montezumae, but this provesnot to be the case. My singlespecimen is not trenchantlyseparable from the femaleof ocellatus(!), and this developmentconsequently endorses Mr. Peters's suspicionthat salleiand ocellatuswould prove to be subspeciesof montezumae(of. 'Birdsof theWorld,' vol. 2, p. 57, footnote,1934). Porzanacarolina (Linnaeus).--1 •, in breedingplumage, Omilteme, May 29, 1936, "ovariesslightly enlarged." The locality and the extremelylate date would both appear to be remarkable. Larus pipixcanWagler.--lc•, in full breedingplumage, Mngileca, April 16. Already known as a transient to the Pacific coast of Mexico and the lakes in the central plateau. Oreopeleiaalbifacies rubida (Nelson).--3c•, 4 •, Omilteme. There are now four subspeciesof this Quail-Dove,of whichrubida is perhapsthe most distinctin its conspicuouslymore cinnamomeous (less clay-color or grayish)underparts. While very slightlybrowner on the occiputthan typicalalbifacies, this character is marked only in anthonyi Griseom of western Guatemala. Oreopeleiamontana (Linnaeus).--1 •, Jaleaca, June' 6. TheRuddy Quail-Dove is well known from the tropicallowlands of Vera Cruz, but from westernMexico hasbeen previously reported once only (Arroyode Liraones,Sinaloa). Ara militarismexicana Ridgway.--1 •, Omilteme.The onlyrecord for Guerrero is Acapulco on the coast. Amazonafinschi (Sclater).--3c•, 2 •, Rinconand Isguagilite. One of the many Tropical-Zone birds hitherto overlookedin Guerrero. Strix variasartorii (Ridgway).--1 •, Omilteme. Ciccabavirgata amplonotata Kelso.--2 •, Omiltemeand Isguagilite.This recently proposedsubspecies, though possessingpurely intermediatecharacters, is quite distinctand occupies a sufficient geographic area to be worthyof recognition. Glaucidiumminutissimum palmarum Nelson.--1 •, Omilteme,April 20. Sorare a bird that an additionalspecimen is worthrecording. Chloroceryleamericana septentrionalis (Sharpe).--1 c•, 2 •. That tbiswearisomely commonlittle kingfisheris previouslyunrecorded from Guerreromerely shows how sketchyis the explorationof this State. Pha•thornislongirostris mexicanus Harterr.--1 • ?, Omilteme. A very distinct subspeciesin its radicallylarger size and generally darker coloration. In spiteof its name,it is onlyknown from Guerreroand western Oaxaca, and would appear to be decidedly uncommon. Campylopterushemileucurus (Lichtenstein).--lc•, Omilteme. A characteristic Subtropical-Zonehummer, here at theextreme northwestern limit of its range. Eupherusapoliocerca Elliot.--1 c• ad., 4 •, Omilteme. Probablythe rarestof Mexicanhummers in collections.This is apparentlythe fifth timeit hasever been collected. Lampornisamethystinus margaritae (Salvin and Godman).--33c•,8 •, Omilteme, the greatmajority breeding. When Ridgway treated the hummingbirdsin Part 5 (1911)of the 'Birdsof Northand Middle America,' this species (in the aggregate 194 GRmCO•,Birds from Omilteme, Guerrero [Al•rilAuk sense)was very rare in collections,and hopelesslyinadequate material apparently inducedhim merely to follow the old-fashionedcriteria handeddown from previous decades. It is of interest to recall that Ridgway's material was as follows:amethyst- inus, 9c•, no females; brevirostris,2c•, no females; salvini, 2c•, no females; mar- garitae,10c•, 2 •2; pringlei, 3•, 1 •. The group was divided into three 'species' on the basisof the color of the throat in males: amethystinusand subspeciesbreviro- stris (Ridgway, 1908) and salvini (Ridgway, 1908) with throat purple to reddishor pinkish purple; margaritaewith throat violet; pringleiwith throat violet blue. This situation proves to parallel that in Amazilia violiceps,where multiplication of specieshad proceededto remarkablelengths. In Lampornisnot only do three speciesbofi down to one, but all thesenames cannot even be usedfor subspecific concepts. It follows,therefore, that Harterr ('Das Tierreich,Trochilidae,' pp. 114- 115, 1900) was entirely correctin reducingthree speciesto one. His only 'mistake' was possiblyin not goingfar enoughin the reductionof subspecies.My conceptof geographicvariation follows:-- 1. Typical amethystinusSwainson. Type locality, Temascaltepec,Mexico. Range now known to extend north to Nuevo Leon, San Luis Potosi and southern Tamaulipas (Galindo). In reality a pale northeasternextreme, certain specimens minutely larger than any others from Mexico. Underparts in both sexespaler brownishgray than in any other race. Throat of adult malesdistinctly more reddish or pinkishpurple than in any other race, the feathersmore widely marginedwith buffy grayish,producing a distinctly squareateeffect. Wing 65-71 mm.; culmen, 20-23. All the remaining subspeciesdiffer from amethystinusand agree minutely with each other in being much darker below (deep mousegray to slate gray), and the throat feathers of adult males are more narrowly margined with paler, giving a less squamateeffect. Immature femalesand males differ from adult femalesin having little or no cinnamomeouson throat, a character which has been alleged to be spe- cific. The usual individual variation in the relative bronzy or green tone to the upperpartshas alsobeen alleged as a specificcharacter. 2. salvini (Ridgway). Highlands of Guatemala. Easily separablefrom typical amethystinusin its darker colorationbelow and slightly smallersize. Wing 64.5-66.5 mm.; culmen,19-21. Throat of adult malesmore reddish, less pinkish purple. The relatively darker auricular area, and the broader, purer-whitepostocular streak are purelymatters of individualvariation and do not affordracial characters. 3. nobilisGriscom. Highlandsof Hondurasexcept the more easternand coastal ranges. Even darker and muchsmaller than salvini,but throat of adult male as in salvini. Wing 59-64 mm. 4. brevirostris(Ridgway). Known from three localitiesonly in western Mexico (Jalisco,Colima and Tepic). The femaleis unknown,and there are only two males in this country. The singlemale before me is indistinguishablefrom largerspecimens of salvini.t We have here consequentlya most anomaloussituation. The real facts are that brevirostrisis an intermediatebetween typical amethystinusand margaritae, but very muchnearer the latter, aslater commentwill show. It shouldbe regarded as a synonymof the latter, unlessa goodseries of adult malesshould show a miracu- lousconstancy in the colorof the throat, whichis noticeablynot the casewith other subspecies. 5. margaritae(Salvin and Godman). Definitelyincluding L. pringlei (Nelson, 1897)and probably also brevirostris (Ridgway). Originallydescribed from Omilteme. Erroneouslyreported by O. T. Baronfrom Chilpancingo,but actuallynot occurring Vol.1937 541] GRISCOM,Birds from Omilteme, Guerrero 195 nearer to this city than the mountains 2000 feet higher. The type of L. pringlei Nelson comesfrom fifteen miles west of Oaxaca City, Oaxaca; all other recorded specimenscome from the mountainsabove Chilpancingo. The great seriesof thirty-three perfect skins of breedingadult males before me reveaJsmost interestingfacts in individualvariation. Twenty-ninespecimens have violet or violet-purplethroats and obviouslyagree with an old British specimenof margaritae. Three have violet-blue or bluish-purplethroats and are consequently L. pringlei. One is even more interesting in that the throat is reddish violet, a shadeexactly half-way betweenthe colorof brevirostrisand that of .margaritae. In the series of twenty-nine 'typical' margaritae, a number of specimensare variously intermediate toward the extreme of pringlei. It should be clear, therefore, that the specificcharacter of L. pringleiis a purely individual variation of margaritae,that the allegedspecific character in the throat colorof margaritaeis of subspecificvalue only,and that the throat colorof brevirostrisis sonearly approximated by the reddest extreme of margaritaeas to impugn the sole character for this subspeciesuntil a proper seriesendorses it. To sumup, margarilaeis an excellentsubspecies, with the sizeof typicalamethyst- inus, the darker colorationof salvini, and the throat of adult males always notably bluer or more purplish,less reddish violet. Arthis heloisaheloisa (Nelson and /)elattre).--2 •, Omilteme. Omitted in error from my previouslist. Aulacorhynchusprasinus wagleri (Sturm).--3•, I 9, Omilteme. While clearly only a subspeciesof prasinus,wagleri is more differentfrom the three other racesof this toucanet than is any one of them from each of the others. Grailaria guatimalensisochraceiventris Nelson.--4c•, 2 9, Omilteme. Much the most distinct of the Middle-Americansubspecies of guatimalensis.The larger size is a character common to most of the endemic races of the Passeriformes. Xenicopsoidesmontanus variegaticeps (Sclater).--3 •, 2 9, Omilteme. This fresh seriesin connectionwith one (old and foxed) from southeasternMexico and four from Guatemalainduces me for the first time to believethat idoneusBangs can be recognized. It was originallydescribed as a specialtyof the Volcan de Chiriqui, and Costa Rican birdswere referredto true variega•iceps.This treatmentproved untenablealmost at once, and idoneushas been buried in synonymyever since. While freely admittingthe variable colorationof this species,it seemsto me that good seriesfrom Hondurassouthward are distinctly darker especiallybelow, more brownishor rufescent,less buffy or claycolor, and aboveall the pileumis a browner, lesspure gray, not in suchsharp contrast to the colorof the back, as is true of the mostnorthern birds when recentlycollected and not foxedwith age. Automolusrubiginosus guerrerensis Salvin and Godman.--1•, Isguagilite, May 15, not breeding. While this bird clearly'represents' the rare rubiginosusgroup, it is largelya matter of opinionwhether to treat it as specificaJlydistinct or not. It is, of course,strikingly different from rubiginosusand veraepacisin beingpaler and browner,less rulescent, throughout. 'The pileumis concolorwith the backinstead of rich chestnutin sharp contrast,and the wingsare but slightlymore rulescent than the back. Other forms farther south must also be considered in this connection. In particularrufipeclus Bangs of SantaMarta bridgesthe gap betweenveraepacis and guerrerens/sto so surprisinga degreethat Hellmayr is undoubtedlyright in combiningall thesebirds under one specificname. There are nowenough specimens to appreciatethe markeddifference in coloration betweenadults and iramatures.The latter are alwayspaler, less richly colored 196 GRISCOM,Birdsfrom Omilteme, Guerrero [April[Auk below, with the tawny, rufous or cinnamon tone to the throat and chest lacking or lessclearly indicated. Ignoranceof this fact in the past has led to the descriptionof two other 'species/A. pectoralisNelson ( = guerrerensis),and A. xanthippeDavison, a synonym of fumosus. In this connectionumbrinus Salvin and Godman of the Pacific Cordilleraof Guatemalahas enioyedan unmeritedreputation for distinct- ness,as its great rarity has prevented the discovery of the real facts. The original diagnosiscorrectly comparedthe young umbrinuswith adult veraepacis,but fresh adults of the former are much lessdistinct. Thus the specimenfrom Chiapasand another from northern Honduras discussedby Hellmayr (' Birds of the Americas,' pt. 4, p. 215, footnote, 1925) are undoubtedlyspecimens of •mbrinus, not veraepacis, and the respectsin which they differ from real veraepacisfurnish an excellent diag- nosisfor umbrinus,which now has a logicalrange from the mountainsof Chiapas through the Pacific Cordillera of Guatemala to the mountainsof central and western Honduras. This subspeciesaverages minutely paler, a little lessrichly rufescenton throat and chest, but the back is distinctly browner, with the chestnut pileurn in sharper contrast. So far as yet known, veraepacisis confined to the highlands of Vera Paz, east of the Altos, in Guatemala. If it occurselsewhere it should be sought in the ranges of eastern and northeastern Honduras, where alone other Vera Paz specialtieshave been discoveredin recent years. Xiphocolaptes promeropirhynchusomiltemensis Nelson.--2•, 4Q, Omllteme. This excellentseries of this distinctly larger, paler and duller subspecies,is far more different from emigransof northern Central America than is costaricensisRidgway. Xiphorbynchuserythropygius erythropygius (Sclater).--1 •, Omi]teme. The rarity of this bird in collectionshas made any study of geographicvariation impossibleup to the presenttime. It is now well known how variable are these woodhewersin coloration,but it has not been so clearly recognizedthat immature birds are astonish- ingly smaller than adults. The measurements in older texts consequently give a remarkable degreeof individual variation. It is only in recent years that erythropy- gi•s has been proved to range commonly southward through Honduras to the mountains of north-central Nicaragua, so that the geographicgap between it and punclig•la (Ridgway) is practically closed. The fine seriesavailable requires a slight modification of the currently alleged diagnosticcharacters:-- (a) typical erythropygius(Sclater).--Type from Jalapa, Vera Cruz. A rare bird, found north of the Isthmus of Tehuantepeconly. Abruptly larger than more southern specimens;of duller, less greenish-olivecoloration below; chin and upper throat whiter, barred with dusky; pileurn more heavily spotted with buffy; back broadly streaked with buffy; underparts heavily spotted. (b) Xiphorhynchus erythropygius parvus subsp. nov.--Type: no. 158,227, Mus. Comp. Zool., • adult; Las Pefiitas, south-central Honduras, February 17, 1933; C. F. Underwood. Slightly richer, more rufescentbrown above; more greenisholive below; chin and throat buffier, spotted with dusky; back lessheavily streaked;abruptly and ob- viously smaller. Seriesfrom Guatemala are intermediate in that they are duller coloredand more heavily streakedon the back; the chin is whitish, but spotted;on the other hand they are smaller than Honduras series. (c) punctigula (Ridgway).--Minutely more olive above and below; underparts lessheavily spotted; intermediate betweenthe two last in size; obviouslydifferent in that the back is unstreaked, or with a few small streaks on anterior portion only; pileam lessspotted. vo,.1937 J GRISCOM,Birds from Omilteme, Guerrero 197

Table of Wing Lengths Mexico: three adults, 122-125 mm.; two young, 108-109.5 Guatemala: eleven adults, 106.5-112.5 mm.; three young, 99.5-101.5 Honduras: ten adults, 110-118 (122) mm.; two young, 103-105 Nicaragua: one adult, 112 mm. The differencesin colorationare so relatively slight, that in spite of the minor differencesbetween Guatemala and Honduras specimens,I prefer to recognizeone smaller race only. The Honduras and Nicaraguan birds are in reality intermediate betweenpunctigula and the Guatemalaseries. There is also an interestingzonal break: erythropygiusis strictly a Subtropical-Zonebird from north-centralNicaragua northward; punctigulaand insolitusare strictly humid Tropical-Zonebirds of the lower levels from southeasternNicaragua southward. Attila spadiceacinnamomea (Lawrence).--1 •, Omilteme. Empidonaxdi.•cilis salvini Ridgway.--3 •, I q}, Omilteme. This is bairdi of my previouspaper, a name which van Rossemhas shownto apply to another species. Megarhynch•s pitangua mexicanus (Lafresnaye).--lc•, 1 q}, Isguagilite. Pre- viously unrecorded from Guerrero. These birds show no approach to caniceps Ridgway of Jalisco. Xanthouralu•cuosa vivida Ridgway.--7 c•, 5 •, Isguagilite and Rincon. ' The sub- speciesof GuerreroGreen Jays was left unsettledby Ridgway for lack of specimens. The presentfine seriesis clearly vividaand showsno approachto speciosaNelson, known from the type locality only, in Jalisco. Aphelocomaunicvlor guerrerensis Nelson.--12c•, 8 •, Omilteme. This fine jay haspreviously been known from only the type seriesin the U.S. BiologicalSurvey. While a very distinct race, it has no claims to specificdistinctness whatever. As stated in the original diagnosis,it is a much darker, more purplishblue than typical unicolorof easternMexico, and consequentlyis still darker than coeleslisof Chiapas and Guatemala. The phrase "much larger" must have been an inadvertence, as the measurementsof the original seriesclearly show;the wing length averagesonly 3 mm. more, surelya minute percentageof 160 mm. !; the tail, however,is appreciably longer in proportion. In colorationguerrerensis is even darker than griscomivan Rossemof Salvador and western Honduras. This latter form averageslarger than •nicolor, but lacks the proportionatelylonger tall (cf. van Rossem,Auk, vol. 45, pp. 362-363, 1928). Cyanolycamirabilis Nelson.--3 c•, 6 •, Omilteme. A beautifully distinct species, even though related to nana of eastern Mexico and argentigulaof Costa Rica. To reducethese three isolatedbirds to subspeciesseems to me to be carrying the ' formen- kreis' theory to absurd lengths. An immature bird is a duller and grayer blue throughout, the chest is sooty below the white throat patch, instead of sharply black, and the pileumis alsofaintly tingedwith sootyonly, insteadof sharplyblack. Previously known only from the type seriesof 3 c•, 2 •. Parus sclaterisclateri Kleinschmidt.--2 •, Omilteme. Troglodytesbrunneicollis brunneicollis Sclater.--3•, 2 •, Omilteme. In the re- view of this speciesin my previouspaper (loc.cit., pp. 394-395) I commentedon the fact that the only specimenfrom Guerrero was paler and duller than typical brun- neicol•isof southeasternMexico, partly approaching ccmpositus Griscom of Tamauli- pas. The presentseries does not confirm the departure of Guerrero birds from the typical. As usual, adults prove to be lessrichly colored. Henicorhinaleucophrys festiva Nelson.--l•, Omilteme. This well-marked sub- 198 oRsco,Birds from Omilteme, Guerrero tAprtl[Auk speciesis a dullerand paler-coloredbird than mexicanawith a lesscontrasted pileurn. It is consequentlyeven paler and duller than the much larger capitalis Nelson of western Guatemala. Hylocichlaguttara auduboni (Baird).--3 c•, 2 9, Omilteme. Reportedhere be- causeone of the maleswas collectedon the astonishinglylate date of May 1, 1936, "testesslightly enlarged." The assumption,however, that the bird was about to breed in the near vicinity, is entirely unwarranted on this evidence. Catharusoccidentalis fulvescens Nelson.--5c•, 6 •, Omilteme. Calharusfrantzii omiltemensisRidgway.--3 c•, 4 Q, Omilteme. Previouslyknown from the unique type only. We have here a most unusualcase of convergenceof characters. This subspeciesis very distinct from its nearestrelative, alticolaSalvin and Godmanof westernGuatemala, in that it is a much paler and duller-colored bird especiallybelow, and the russettone of the pileurn is so faint in the majority of the seriesas not to furnish any strong contrastwith the olivaceous-brownback. Now it so happensthat thesecharacters are preciselythose which separateC. oc- cidentalisfulvescens Nelson from typical occidentalisof southeasternMexico. To thosefamiliar with both birds, occidentalisand typical frantzii are obviouslydistinct species,separable by color charactersat a mere glance at skins in a tray. These differences,however, completelydisappear in the two representativesubspecies from Omilteme. The two series are virtually interchangeable,unless the real, fundamentalspecific characters are used. Theseare (1) the wholly yellow mandible in frantzii, whereasthe terminal half of the mandible is blackish in occidentalis;(2) the inner websof the basesof the remigesin occidentalisare abruptly buffy, forming a distinctbuffy patch at the baseof the spreadwing, which is otherwisegrayish on the under surface. These differencesare much lesspronounced in immature speci- mens. Ridgwayia pinicola (Sclater).--3c•, 2 •, 1 juv. c•, Omilteme. The discovery of possiblegeographic variation in this little-known thrush still awaits the assembly of adequateseries of all three plumages. Vireolanius melitophrys melitophrys DuBus.--lc•, Omilteme. Listed in my previouspaper as galdmaniNelson. I have sinceshown (Ibis, p. 552, 1935) that the charactersof this allegedsubspecies were based entirely on the immature plumage of melitophrys. Cardellina rubrifrot•srubrifrons (Giraud).--1 c•, 2 •, Omilteme. Myioborusminiatus miniatus (Swainson).--2c•, 4 Q, Omilteme. Basileuterusbdli clarus Ridgway.--1 c•, Omilteme. Apparently the secondtime this bird has ever been collected. Distinctly lighter, brighter and yellower than scilulusNelson of Guatemala,but I am not impressedby the "much longertarsus." Icterus melanocephalusmelanocephalus (Wagler).--3c•, 2 •, Omilteme and Rin- con. The tenth memberof the genusto be recordedfrom Guerrero! Piranga bidentala bidentata Swainson.--3c•, Omilteme. Provisionally referred here until the variationsof the speciesin Mexico canbe properlystudied. Clearly not sanguinolenta(L•fresnaye), if this is properly representedby Vera Cruz speci- mens. Hesperiphonaabeillii abeillii (Lesson).--1 9, Omilteme. While new to Guerrero, this specimenshows no approachto the charactersof the unique type female of pallida Nelson. Ss,lts, tor s,•iceps fis,vicrissus subsp.nov.--Type: No. 172,345, Mus. Comp. Zool.;breeding c•; Isguagilite,Guerrero; May 15, 1936;W. W. Brown,Jr. Nearestto typical atricepsLesson of Mexico, here restrictedto Vera Cruz, but black pectoral Vol.1927 541J GRISCOM,Birds from Omilteme, Guerrero 199 collar averagingbroader, lessbroken with white feathers; white throat patch con- sequently averaging smaller; flanks lesswashed with brownish or olive; crissumand undertail covertsmore olive ochraceous,less orange. 4 c•, 2 9 from the type locality. The Museum of Comparative Zoology happensto possessa practically perfect seriesof this species. Variation of plumagewith agehas never been properly brought out. Ridgway'sdescription of the 'young' r•ally appliesto the juvenaljust after being fledged. In this plumage the maxilla is yellow, the black of head, chin and chestis dnller; the white throat patch is smaller, lesssharply defined,and the feathers have a characteristicallyloose and fluffy texture. This plumage is followed by the very different immature plumage,in which the maxilla is still yellow, but the whole throat and chestis white with a varying amount of black feathers,where the pectoral collar should be. The specimensbefore me seem to show that the bill becomes black before the black pectoral collar is assumed. Two from eastern Guatemala, for instance,have no pectoral collar, but only the tip of the maxilla is yellow, while the majority of specimensof typical atriceps from Mexico and northern Central America without black pectoral collar have solid-blackbills. It follows,therefore, that immature specimensof typical atricepsexactly resemble adults of lacertosus Bangs of Panama, which are devoid of a pectoral collar, and this subspeciesis posi- tively characterizedby the gray insteadof black auricnlars. It is alsomost helpful to have skins of the same make-up. Fortunately again we have perfect skins by Brown from Vera Cruz, Oaxaca, and Guerrero. It should be clear that the width and distinctnessof the pectoral collar would be affectedby the degreeto which the breast is stuffed or the head and neck bent backward. Like a great many other birdsof easternMexico, typical atricepscrosses the conti- nent at the Isthmus of Tehuantepec and from there south occurson the Pacific as well as the Caribbeanslope of Central America; 53 specimensfrom the Isthmus south to Nicaragua are inseparablefrom 17 specimensfrom southeasternMexico. The type and six other specimensfrom Yucatan and Quintana Roo represent raptor (Cabot), a notably paler bird below,adults of which apparentlyhave a nar- rower and more broken collar than adult atriceps,though immature.birds are, of course, indistinguishablein this respect. The type and fifteen other specimens adequatelyrepresent lacertosus Bangs. It shouldbe noted that this speciesis previouslyunknown in westernMexico, so it is not surprisingthat the Guerrerobird shouldprove separable. Museumof ComparativeZoology, Cambridge,Mass.