A BRIEF ACCOUNT OF THE GENERA AND SPECIES OF LOCUSTS OR GRASSHOPPERS OF ARGEN- TINA, TOGETHER WITH DESCRIP- TIONS OF NEW FORMS.
Incidentlaly while studying- the migratory locust of Argentina, the writer made notes on a number of the various other species of locusts found in the Republic that came under his observation. He also had collections of these inscets made in several portions of the country. Additional material was likewise obtained from Dr. Hugo Stempelmann of Rosario, - Sante Fe, Federico Schulz, of Cordoba, and Masters Oliver and William Thomas of Carcarana, F. C. C. A., thereby bringing together a sufticient number of forms to at least indicate, in a general way, what sort of a locust fauna occurs here. The results were so satisfactory that about a month before leaving Argentina for the United States the writer conceived the idea of preparing* a paper on the "locusts of Argentina" which should, so far as possible, contain a mention of all the described species found in the country, along with descriptions of any possible new forms that might be brought together for such a purpose. Efforts were therefore made to secure the material contained in both the National and La Plata museums for study so as to make this paper as nearly complete as possible. This last mentioned project failed, hence the species represented in these two collections are not recorded here, although several rare and perhaps additional new forms are known to be represented. The present paper has been suggested chiefly on acco unt of the number of other species of these insects that have heretofore shown a tendency to increase to such abnormal
14 numbers as to become local pests. Each of these will be described more or less fullv in connection with its name in the proper place.
The two papers on Argentine Orthoptera by Dr. E. Giglio-Tos of Torin, Italy, have been of much value in forming a basis upon which to build. The drawings for the illustrations used here were made by Miss Edna L. Hyatt, Artist for several of the departments in the University of Nebraska.
The following table for the separation of the principal groups of subfamilies of locusts along with such as follow will aid the reader in obtaining the names of any of these insects mentioned here and that may come under his observation.
TABLE FOK DETERMINING THE SUB-FAMILIES OF ARGENTINA LOCUSTS.
A. Claws of feet without cushion or arolium between them: pronotum extendintj over the abdomen; tegmina or front wings h)l)iform. TETTIGIN^E.
AA. Chiws with cushion or arolium present; not extending over the abdomen, b. Antenna' or feelers shorter than the front femora or thighs. c. Head short, compressed in front. UMASTACINiE. ce. Head greatlv elongiited, bodv apterous or subai)terous. PKOSCOPIXiE.
bb. Antenna' longer than the front femora. e. Posternum or breast between base of front pair of legs smooth, not provided witli a tubercle, swelling, or spine d. Fastigium of the vertex but little declivious, meeting the face in a more or less wcli-detined angle, the face usually very obliciue. Wings as a rale without a dusky band. TKYXALINyE.
dd. Fastigium of the vertex rounded at its point of junction with face, the latter vertical or nearly .so. Wings when present usuallv with coloretl disk and well defined dusky band . 0 1 :i> IPO 1 ) 1 N .K.
cc. Posternumor breast between base of front pair of legs laniinately elevated in front, tubercnlate or spined.
d. F'oveohe of the vertex above, contiguous, forming the apex of the fastigium (Fig. 15). Rather clumsy insects, usually without, or with abbreviated wings, but occasionallv with these appendages complete. PYRGO^KNiPH I N.^j] dd. Foveohe of the vertex lateral, never forming the ajjcx of the vertex, often closed behind or entirely w.uitiiig. I'rostcrnum distinctlv spined or tubercnlate. Winu- varion-lv formed. ACHIDI IN /fri.
15 SUB-FAMILY TETTIGINAE.
This sub-famtly of locusts is represented in Argentina by a comparatively small number of inconspicuous insects none of which ever become sufficiently numerous to cause any particular damage. They all live in rather damp localities along the margins of streams or in the vicinity of swamps, where they may be found in greater or lesser numbers upon the mud flats. These insects are known as "Grouse Locust.s" and are represented in the Republic by less than a dozen species belonging to the following genera as indicated by specimens and records. They may be determined by the table for the separation of genera as given herewith. TABLE OF GENERA.
A. Front thighs more or less carinated above: front margin of pronotnm in middle not advanced upon the back of head, b. Body, even of the female, quite slender, the a])ex of pronotnm greatly extended beyond the tip of hind femora. NKPHKLE Bolivar.
bb. Body in -both sexes obese, the apex of pronotum not at all or but little extended beyond the tip of hind femora. PAKATETTIX Bolivar.
AA. Front thighs not compressed, rather broadly and distinctly grooved: front margin of pronotum in middle angulate and advanced upon the occiput. TETTIGIDEA Scudder.
GENUS NEPHELE, BOLIVAR.
Xephele gracilis n. sjd. Closely related to N. fKir/ida Bol. but considerably smaller. Antennae with last or terminal joint the same color as the rest ; the vertex as in that species. The pronotum extending nearly one- half of its length beyond the tij) of the hind femora, its median carina laminately elevated in advance of the humeral angles. Color dark brownish fuscous. In some specimens more or less marked with the usual blotches of black and ochraceous on the disk between the humeral angles.
Length: of body, d", 6 mm, V , 8 mm; of pronotum, d' , 12 mm, ? , 13 mm; of hind femora, d, 2 mm. ? , 5.25 mm. I have seen specimens of this insect collected at Cordoba (F. Schulz), and others from Paraguay and Territory of Formosa, Argentina (Dr. H. Stempelmann).
16 GENUS PARATETTIX, BOLIVAR.
TABLE FOR SEPARATION OF SPECIES.
A. First and third joints of hind tai'si of eqnal length Carina' of the femora entire. peruviaiius Bol.
AA. First joint of hind tarsi longer than the third. Carinii' of the femora undulate, b. Carina' of anterior femora undulate. Pronotum generally shorter than tip of hind femora. Pronotum with carina on anterior portion rather high. Borellii (Tiglio-Tos.
bb. Carina' of anterior femora leaf-like. Pronotum greatly surpassing tip of hind femora. ciieiiiiclotiis Burm. P. penivkiims Bol. This locust has been taken at San Lorenzo, m the province of Jujuy. (Gi^lio-Tos.) P. oiemidotus Burmy Giglio-Tos also rej^orts that a specimen from the same locality has been referred with doubt to this species.
P. Borellii Giglio-Tos. This insect has been collected in a number of localities, as San Lorenzo, Jujuy, Tucuman. Cruz del Eje, Cordoba, Carcarana, Rosario, and Buenos Aires. It is evidently the most abundant species found in the Rejiublic, and occurs in two forms as reagrds pronotum length. It can at once be recognized by the rather prominent tubercles on the outer face of the hind femora which, when observed from above, project considerably beyond the other portions of these legs.
Giglio-Tos, in his report on the Orthoptera of the "Viaggio del dott. Alfredo Borelli nella Republica Argentina e nel Paraguay", referred a single specimen of this insect with much doubt to ParatetUx tolfecus Sauss. (Bolletino dei Musei di Zoologia ed Anatomia comparata della R. Universita di Torino, Vol. IX, No. 184, p. 5.) but in a later paper has described it under the above mentioned name. GENUS TETTIGIDEA, SCUDDER.
TABLE FOR SEPARATION OF SPECIES A. Body obese, the ])ronotum extending but little if any Ixiyond tip of hind femora. ' nuilticostata Bol.
A. v. Body graceful, the pronotum greatly surpassing the tip of hind femora. j»-va<'ilis Brunei-.
17 T. niu/f/rostafa Bol. This insect is quite common from Tucuman northward through the j^rovinces of Salta and Jujuy. (Giglio-Tos. ) Tettigidea gracilif> n. sj). A beautiful, very slender, dark br£)wn species with long pronotum in which the supplemental carinae are continuous and nearly or quite as prominent as the middle and lateral ones. Vertex somewhat advanced in front of the eyes, the sides rounded, median carina prominent, considerably advanced in front of the sides where it unites with the frontal costa the sulcation of which begins on a level with the vertex. Face somewhat oblique. Last joints of palpi w^hite and very conspicuous. Pronotum angulate in front and terminating in a rather prominent spine which projects forward upon the occiput beyond the middle of the eyes. Tegmina rather long, narrow, and provided with a whitish cicatrice near the apex which is roundly and obliquely truncated from below. Valves of the ovipositor unusually long, straight and slender, especially the lower pair which are dagger-like and almost without teeth.
Length: of body, 11 mm; of jDronotum, 18.5mm; of hind femora, 5.5 mm.
Only a single female specimen of this insect has been seen by the writer. It was captured on some bags of grain on the decks of a river steamer lying at anchor near the wharf of Corrientes.
SUB-FAMILY EUMASTACINAE.
Thus far this sub-family is not definitely known to exist by actual observation within the boundaries of the Republic ; but, since several species have been taken in the closely adjoining portions of Paraguay and Bolivia, it may be taken for granted that at least one or two forms will occur in the northern portions, as for example the territories of Formosa and Chaco, and the jorovinces of Salta and Jujuy. These insects, like the representatives of the preceding sub-family, never become sufficiently numerous to cause damage to
18 cultivated vegetation, hence need not be taken into serious consideration in a treatise on destructive locusts. The f olowing three or four species maj^ be looked for in the territory mentioned above.
TABLE FOR DETERMINATION OF GENERA.
A. Fastigium of the vertex very narrow, scarcely or not at all ])rojecting in advance of the eyes. EUMASTAX Burr.
A A. Fastigium of the vertex wider and more or less ])rojectlng in advance of the eyes. MASYNTES Karsch.
GENUS EUMASTAX, BURR.
This generic name has recently been suggested by Malcolm Burr (Anales de la Sociedad Espanola de Historia Natural, Vol. XXVIII, 1899) in place of Mastax Perty, which had been used several years before in Coleoptera. This being the tyi3ical genus of the sub-family necessitated the changing of that name also.
TABLE FOR THE DETERMINATION OF THE SPECIES. A. Apex of the vertex above the eyes, when viewed from the side, not visible. Tegmiua and wings fully developed. Posterior femora irregularly black spotted. pardaliua Burr. A A. Apex of the vertex above the eyes when viewed from the side ])lainly visible. Detiexed lobes of the protonum with the anterior angle obtuse. versicolor Burr.
Eumafitax pardallna Burr, Essai sur les Eumastacides, p. 51. This insect was described as coming from Paraguay, and is liable to occur in northern Argentina. EumoHtax versicolor Burr, loc. cit. p. 54, also a Paraguayan species, and might likewise occur in the Territory of the Chaco.
GENUS MASYNTES, KARSCH.
TABLE FOR THE DETERMINATION OF THE SPECIES. A. Tegmina lobiform, elliptical, the apex broadly rounded. Pronotum truncate behind, the middle minutely notched. Borellii Giglio-Tos.
AA. Tegmina and wings perfectly developed. Pronotum "rounded behind, the middle not notched. tigTi.s Burr. iVmyntes Bm-elUi Giglio-Tos, Boll. Mus. Torino, Vol. XII, No. 802, p. 17, 1897.
10 This i^eculiar locust has been taken at San Pedro, Paraguay (Giglio-Tos) and is liable to occur in the Chaco country.
3f(/si/n.fe-s tigris Burr, Essai sur les Eumastacides, p. 62. Like the preceding species this is a Paraguayan locust to be looked for in the territories of Formosa and Chaco. SUB-FAMILY PROSCOPINAE.
As indicated in the table for determining the sub-families of locusts it will be seen that the insects belonging to this sub-family are rather long, wingless, and resemble to a certain extent the different species of walking sticks, or stick insects. Thus far there have been reported from Argentina thirteen distinct species. They belong to the two genera that may be separated by the accompanying table. TABLE OF GENERA.
A. Pronotum cylindrical, not separated from the prosteruum by longitudinal lines. Body comparatively heavy in the female: antenna^ nearly as long or a tritle longer than the vertex. TI:TAN<)HHYXCHI S Bmnner.
AA. Pronotum more or less flattened from a))ove. divided from the prosternum by a longitudinal line. Bcjdy long and slemler even in the female; the vertex in both sexes advanced beyond the tip of the antennae. CKPHALOCOEMA Serville.
GENUS TETANORHYNGHUS, BRUNNER.
TABLE FOR THE SEPARATION OF THE SPECIES.
A. Rostrum of the female distinctlj^ shorter than the remainder of head, attenuated towards the apex. liumiHs Giglio-Tos. AA. Rostrum of the female distinctly longer than the remainder of head. b. Rostrum with the apex sti'ongly clavate, posterior tibi.-v armed above with 14-22 spines on the inner and outer rows. Borellii Giglis-Tos.
bl). Rostrum attenuate towards the apex. Posterior tibia' armed above with 13 spines on the inner and outer rows. aiigustirostris Brunner.
T. /lumilis Giglio-Tos. San Lorenzo, Province of Jujuy and northward. (Giglio-Tos.)
T. Borellii Giglio-Tos. Same localities as the xn-eceding, and likewise Bolivia. (Giglio-Tos. ) 7'. (ntf/ustiro-'^tris Brunner. San Jose, Republic of Argentina.(Brunner.)
20 GENUS CEPHALOCOEMA, SERVILLE.
TABLE FOR SEPARATION OF THE SPECIES.
A. Rostrum of the vertex scarcely as long as or but little longer than balance of head. Protonnm punctulate or smooth. Tibite above on both sides with not more than sixteen spines, b. Rostrum of the vertex much shorter than the remainder of head. Abdomen tive-ridged. costulata Burm.
bb. Rostrum of the vertex distinctly shorter than or but little longer than remainder of head. Abdomen not tive-ridged. c. More robust: rostrum pyramidal, acuminate, viewed from the front narrowly lamellate. Antenn;e of female greatly surpassing the rostmm. Borellii Giglio-Tos.
cc. More slender: rostrum with the sides parallel, d. Rostrum linear, obtuse, viewed from the front narrowly cruciform. Attenn.-e of female a little surpassing the rostrum. Caizana Giglio-Tos.
dd. Rostrum quadrangular, obtuse, as long as (female) or longer (male) than the rest of head. oalainus Burm. AA. Rostrum much (two or more times) longer than the remainder of head b. Protonum longer than the head.
c. Protonum with the anterior margin not tuberculate. d. Rostrum less than twice the length of remainder of head, moderately dilated toward the apex. obtiisa Giglio-Tos. dd. Rostrum fully twice as long as remainder of head, strongly dilated toward the apex. niag'iia Giglio-Tos. cc. Pronotum with the antei-ior margin bituberculate. gigantea Giglio-Tos.
bb. Protonum shorter than the head.
c. Rostrum less than four times as long as remainder of head, d. Rostrum a tritle more than twice as long as remainder of head: the anterior femora about two-thirds as long as pronotum. teretitiscula Brunner.
dd Rostrum three times as long as remainder of head: the anterior femora a trifle longer than the pronotum. lancea Burm.
cc. Rostrum more than four times as long as remainder of head. liiieata Brunner.
Fig. 6. — Cephaloeoema costulata.: female. C. costulata Burm. This species which occurs over the greater part of the Republic north of tlie Rio Colorado is quite variable in color. (Collections of Stempelmann, Schulz, O. Thomas and others.)