Bueker, Elmer D.

Cockerell, Theodore D. A. (Theodore Dru Alison), 1866-1948.

American Museum of Natural History Scientific Publications

AMERICAN MUSEUM NOVITATESPublished byNumber 441 THE AMF.RICANIu8E17Mu oi NATURAL HISTORY Dec. 18, 193059.57, 52 C (94)SOME GEOPHILOUS MEALY-BUGS FROM AUSTRALIA (HOM-OPTERA: COCCOIDEA)BY T. D. A. COCKERELL AND ELMER D. BUEKERIn 1894, Ripersia maritima Cockerell was described from specimensfound on roots of the grass Spartina at Hempstead Harbor, LongIsland. It occurred between tide-marks, being submerged at each hightide. It was remarked at the time that it showed a very close resem-blance to R. rumicis Maskell, found among roots of Rumex in NewZealand. Since then, other related species have been described fromCalifornia (Ripersiella kelloggi Ehrhorn and Cockerell) and the RockyMountains (R. leucosoma Cockerell); while the British R. halophila(Hardy), found on the roots of grass and other plants, proves to belongto the same group. This series of mealy-bugs is so distinctive in itscharacters, and the species are so similar, that it has been set aside as adistinct genus, Ripersiella Tinsley, 1899. It is, however, perhaps tooclose to Rhizoecus Kiuinckel, 1878, which has five-jointed antennwe.1How does it happen that these coccids, the females of which can crawlonly a short distance, are thus spread over the world? The species aredifferent, and there is no reason to suppose that they have been spreadby commerce. Are they representatives of a type of enormous antiquity,now surviving in certian localities? Other examples from other groupsof coccids can readily be cited, suggesting some occasional mode ofdistribution no less efficient than the ffight of Lepidoptera and Orthop-tera. This, we cannot doubt, is transportation by migrating birds.Many of the shore birds, famous for their migrations, nest on the ground.It is comparatively easy for the newly-hatched larvae of geophilouscoccids to wander on to the body of a bird and be carried hundreds ofmiles in a single night. It is not to be supposed, nor does the evidencesuggest, that this is constantly happening. It will suffice to explain thefacts of distribution if it occurs at rare intervals, the larvae still morerarely surviving the journey and finding a means of living at the otherend. It is obvious that species thus transported will stand a good chanceof survival if they are general feeders, or feed on grass. The specializedcoccids with particular host-plants would stand hardly any chance.1Newstead gives a full account of Rhizoecus terrestris (Newstead), showing the peculiar antenn.AMERICAN MUSEUM NOVITATESThe observed facts seem to agree well enough with these suppositions,and it will be interesting to determine how far geophilous or grass-feed-ing coccids are distributed in remote places or on islands. At the presenttime the records are quite inadequate. It is not so long ago that prac-tically nothing was known of geophilous mealy-bugs in America, yetwe now know that they abound in species and individuals, especiallywhere the nests of the ant Lasius are to be found. From the southernhemisphere the records are few and scattered. Green is constantlyadding species to the recorded fauna of the western Palearctic region.Mrs. Wilmatte P. Cockerell had long collected mealy-bugs understones in New Mexico and Colorado, finding many new species. Con-sequently, when in Australia in 1928, she could not resist turning overlikely looking stones, and was rewarded by the discovery of the twospecies now described. These must be referred to well-known generaof the northern hemisphere, as Pseudococcus hystricosus and Trionymusangustus. The genera of mealy-bugs have been defined in various ways,and are still subject to revision. Newstead (1903) used the followingcharacters:Adult females active, covered with mealy secretion, not enclosed in ovisac; femaleantennae of eight joints.................... Dactylopius (now Pseudococcus).Adult females enclosed within ovisac at gestation;antennt of nine joints....................... Pseudococcus (now Phenacoccus).Antennae of six (rarely five or seven) joints............................. Ripersia.This appears simple, but the facts of nature are more complex, andthe number of antennal joints differs in evidently related species. How-ever, Phenacoccus has a denticle on the claw, which is a good diagnosticcharacter. Ferris (1918) adopted a quite different scheme, stressing theimportance of the cerarii, or groups of spines and pores, which rangefrom none to twenty-four in different species. From these arise tufts ortassels of wax, so that, even when the cerarii have not been described,their existence can be inferred from the external appearance of the ani-mals. The group with a denticle on the claw and the antennae eight-or nine-jointed (usually nine) is divided into three genera: Phenacoccus,Puto (including Ceroputo), and Heterococcus. With these we are not nowconcerned. The other series is first separated into Pseudococcus (thecommon mealy-bugs), with more than four pairs of cerarii, and four othergenera, with not more than four pairs. Here is perhaps a weak point,as the reduction of the cerarii has probably taken place independentlyin several series. Morrison (1925), tabulating a series of mealy-bugs,sets forth the true Pseudococcus (at least as relates to the six species2 [NO. 441MEALY-BUGS FROM AUSTRALIAincluded) as having at least one pair of cerarii present on the head be-tween the antennae. These cephalic cerarii are plainly visible in theAustralian Pseudococcus hystricosus described below, but are whollyabsent from Trionymus angustus. Morrison tabulates! three species ofTrionymus in the paper just cited; in T. sacchari (Cockerell), from sugar-cane, only the apical cerarian spines are present and these not welldeveloped. In the new T. danthonixe from Stewart Island and in T.diminutus (Leonardi) there are no cerarii on the head, but the former hastwo posterior pairs of cerarii, the latter three or four.Trionymus, first described under the preoccupied name Westwoodia,was characterized by the elongated form of the body and eight-jointedantennae. The shape of the body seems usually to be related to life onsome narrow object, as a stem of grass, though T. americanus (Cockerell),which is very slender, occurs in cracks on the trunk of ash trees. Theshape of the body and more numerous antennal joints appear to separateit from Ripersia but, as Ferris states, the definition and limitation ofRipersia are at present uncertain. There can be little doubt that themany species referred to this genus represent, at least in part, a mixtureof generic types. The type of the genus (R. corynephori Signoret), aspecies with sixjointed antennae, is not known to modern workers. Thefood-plant is a grass of southern Europe. It is probable that we mayproperly recognize, following current usage, a genus of geophilous mealy-bugs, mostly found with ants, resembling Trionymus in many respects,but with fewer antennal joints. But such species as Ripersia fimbriatulaCockerell and King will apparently have to be excluded, and it will benecessary to investigate anew the various aberrant species of "Ripersia"to determine what should be done with them.New biological observations are needed. The reported food-plantsmay not always be correct. It is difficult, when a mealy-bug occurs onroots, or (as is commonly the case) on the under surface of stones, todetermine exactly what plant is used for food. Experiments are neededto determine such points, and also to determine how long the newlyhatched larve can survive without feeding.The significance of variation in the number of antennal joints maynot be the same in all cases. Coccid larvae in general have six joints, andthe number in mealy-bugs commonly increases with maturity. Thus, itmay be expected that a species with a maximum of seven joints will showsome individuals with six; or one with nine joints, some with eight.But to have only five joints in the adult (as in Rhizoecus) is more remark-able and represents a different tendency.1930] 3AMERICAN MUSEUM NOVITATESThe specimens of Pseudococcus hystricosus, though well developed,are probably not mature, and it is probable that individuals with eight-segmented antennae will be found. This is suggested by the presence oftwo whorls of hairs on joints two and three. But this is not conclusiveat all, since some species with eight segments (as Pseudococcus u'alkeriNewstead) still show two whorls on each of these segments. The generalcharacter of the antennae is much more like that of Pseudococcus thanRipersia, in spite of the six segments. The species is a very distinct one,remarkable for the densely glandular surface, coarse curved bristles ofthe antennse, long beak, stout femora and long bristles at caudal end.Among the described Australian species it seems nearest to Pseudococcussimilans (Lidgett), found on roots of Daphne in Victoria. This is about4 mm. long, with eight-segmented antenne, and a fringe of long cot-ton-like filaments on each side of the body. Lidgett's figures areextremely crude, and Froggatt states that the type is lost.Trionymus angustus is a very small species, but without very strik-ing characters. In shape and general appearance it closely resembles T.danthoniae and T. diminutus described by Morrison, but the antennae areproportionately very much larger than in these species. The antennalsegments 3 to 6 are broader than long, and the second, though distinctlylonger than broad, is very stout. Thus, the species departs widely fromT. danthoniae and comes nearer to T. diminutus, in which, however, thethird segment is longer than broad. T. angustus is also remarkable forthe single, long and strong, bristle on each caudal lobe, and the posses-sion of only a single pair of cerarii. In the last character it agrees withcertain Californian species, and rather closely approaches T. distichliiFerris, a species with seven-segmented antennae, of which neither thesize nor the shape is given.' The cerarian spines are slender, which wouldmake the species run to T. distichlii in the table given by Ferris (1918).T. angustus and T. distichlii are both forms in which the cerarian struc-tures are reduced nearly to a minimum, but whether they reached thiscondition independently or represent a natural division of the genus it isimpossible to say.Pseudococcus hystricosus, new speciesFEMALE (from slide mounts).-Ovate; length 1.5 mm., width 1 mm.; derm quiteclear, but with numerous triangular glands scattered over the dorsal and ventralsurfaces, also short spines and occasionally long hair; 25-27 large ocular wax-glands'Ferris states that he had T. distichlii from La Jolla, determined by Cockerell as Pseudococcussalinus. He was aware that this was only a field determination, the material coming from the type-locality of P. salinus, and having superficially the same appearance.4 [No. 441MEALY-BUGS FROM AUSTRALIAon the ventral side of the last abdominal segment immediately posterior to thegenital opening, 28-32 on the second segment anterior to the genital opening, sparseon the third and fourth segments; antennae six-segmented; average lengths of seg-ments examined in microns: (1) 48; (2) 45; (3) 53; (4) 20; (5) 35; (6) 78; formula6, 3, 1, 2, 5,4; each joint has stout, curved bristles; segments two and three each withtwo whorls of curved bristles; sixth segment with three whorls of curved bristles anda group of slender straight bristles at the end; legs not unusual and with small stoutbristles; the middle leg with measurements given in microns as follows: coxa withFigs. 1 to 4. Pseudococcus hystricosus, new species.1, dorsal aspect of posterior portion of abdomen of female; 2, ventral aspect of posterior portion ofabdomen of female; 3, middle leg of female; 4, antenna of female.five bristles, length of coxa 60; trochanter with three short bristles and one longbristle 70 in length; length of trochanter 45; femur quite stout, with six short bristles,length of femur 150; tibia with three whorls of bristles, length of tibia 115; tarsuswith three whorls of bristles, length of tarsus 80; claw simple, digitules small; beaktwo-segmented and with numerous stiff bristles at the end, length 150 microns, width100 microns; caudal bristles stout; anal lobes protruding slightly from the marginof the body, apical seta 270 microns long; anal ring with inner and outer pore-bands,outer band with a tube-like duct in each pore; 6 anal ring-setse, 125-150 microns in19301 5AMERICAN MUSEUM NOVITATESlength; seventeen pairs of cerarii, each cerarius of two conical spines and a few tri-angular wax-glands; one pair of cerarii lateral of antennEe, one pair between theantennre.Jenolan, New South Wales, April 29, 1928, (W. P. Cockerell). The locality isin the vicinity of the famous Jenolan caves. Two specimens on the slide; the holo-type is the one with antenna pointing in different directions (Amer. Mus. No. 28458).Trionymus angustus, new speciesFEMALE (from slide mounts).-Body elongated, narrow, sides subparallel; lengthwhen mounted 2 mm., width .6 mm.; derm quite clear with the usual type of tri-angular wax-glands scattered thinly over the surface; ocular wax-glands very numer-ous on the ventral side of the abdominal segments; as many as 80-100 glands on theventral side of the last three segments, gradually becoming fewer on the abdominala~~~~~~~~~Figs. 5 and 6. Trionymus angustus, new species.5, anal lobe cerarius and anal ring of adult female (left), and ventral view of anal lobe (right); 6,middle leg of adult female.segments toward the anterior end; antenne eight-segmented; average lengths ofsegments examined in microns: (1) 45; (2) 47; (3) 23; (4) 20; (5) 30; (6) 22; (7)31; (8) 70. The middle leg with the measurements given in microns is described asfollows: coxa with five bristles, total length of coxa 65; trochanter with three shortbristles and one very long bristle of about 70 microns, length of trochanter 40; femurwith nine bristles, length of femur 180; tibia with three whorls of hairs, length oftibia 150; tarsus with three whorls of hairs; length 75; claw normal with two slenderdigitules which project slightly beyond the claw and have a medium-sized knob on[No. 44161930] MEALY-BUGS FROM AUSTRALIA 7each; legs not unusual, all of them with stout bristles; beak or labium about as broadas long and forming an equilateral triangle, two-segmented; one pair of cerarii whichare located on anal lobes; each cerarius composed of two slender spines and a fewtriangular wax-glands; anal ring with inner and outer pore-bands, outer pore-bandwith an elongated duct in each pore; 6 anal ring-setse, 75-80 microns in length; anallobes slightly protruding, apical seta of each lobe 120-130 microns long.Jennings, New South Wales, April 25, 1928, (W. P. Cockerell). Two specimensfound under a stone in an open grassy field^.The holotype is the one with bothantennw perfect (Amer. Mus. No. 28459).The types of both species are in The American Museum of Natural History.Because of the eight-segmented antennae and the relative lengths oftibia and tarsus, this is, no doubt, a mature form.

Mealy-bugs from Australia

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