Richard Dow.
A New Stizus from Utah, with Notes on the Other North American Species (Hymenoptera: Sphecidae).
Psyche 48(4):171-181, 1941.

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A New Stizus from Utah
A NEW STIZUS FROM UTAH, WITH NOTES ON THE OTHER NORTH AMERICAN SPECIES
(HYM. : SPHECIDE)
BY RICHARD Dow
Reading, Mass.
Stizus iridis, sp. nov.
Male.- Length about 20 mm. Yellow (Amber Yellow of Ridgway) , with the following exceptions : mandibles dark ferruginous at apex with a ferruginous line along the interior margin; supra-antenna1 area with inconspicuous dark spots on each side; a broad transverse black band across the vertex including the ocelli, with an anterior ex- tension along the median frontal groove; occiput with two black or ferruginous bands which connect the sides of the vertex with an extensive black area surrounding the foramen; antenn~ with the posterior surface of the scape, the pedicel, and the flagellum ferruginous, the flagellum shading to black above and to orange toward the apex; pronotum with a black transverse band anteriorly; disk of mesoscutum and anterior margin between posterior lobes of pronotum black, either marked with two narrow yellow- ish longitudinal stripes (h010type)~ or two large spots of reddish brown (paratype), or simply black (paratype) ; dorsal surface of propod'eum with a narrow black fascia along the anterior margin? wider and with a posterior median projection in the paratypes; sutures of propodeal area marked with black lines (partly obsolete in the holo- type) which meet on the posterio~ surface; posterior sur- face with a black line extending anteriorly along the median groove ; proepisterna black except for a small spot near the lateral angle of each front coxa; mesosternum with a large black maculation? medially interrupted in both paratypes, and ferruginous in one of them, emarginate (holotype) or narrowed anteriorly, but posteriorly with only a narrow



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172 Psyche [December
separation (along the ridge representing the mesopleural suture) from a dark spot near the ventral end of the meso-metapleural suture; remainder of mesopIeura, except dorsal portion of mesepisterna, suffused with orange ; rneso- metapleural and metapleural-propodeal sutures marked with black lines ; lateral areas of metasternum black ; all cox= black at base, at least anteriorly; remainder of legs partially suffused with orange; veins and membrane of fore wings yellowish basally, and somewhat fuliginous in the region of the first submarginal and marginal cells, the latter with a dark streak in the anterior half; hind wings yellowish; an- terior face of first tergite more or less ferruginous, with a black basal area which (in the holotype and one paratype) has a narrow median projection and broad extensions at the sides (the other paratype has only a median projection which is shorter and does not reach the dorsal surface) ; apical and to some extent the lateral margins of all tergites orange; basal margins of tergites 2-5 orange or black (always black on tergites 4-51, each with a triangular median projection of the same color; sternites variously marked with orange and black.
Head (in facial view) broader than long, the posterior margin nearly straight; inner margins of eyes nearly straight, slightly converging anteriorly, nearest to each other where they reach the clypeus; clypeus emarginate both anteriorly and posteriorly (fig. I), the peak of its con- vexity (seen in profile) anterior to the middle; supra- elypeal area posteriorly three times as broad as long? the sutures defining the frontal shield (Stirnschildschen) not distinct ; antenna1 sockets separated from the eyes and from each other by somewhat less than their transverse diameter ; space between the antenna1 sockets with a low ridge, cari- nate posteriorly ; supra-antenna1 area with a broad median impression which extends posteriorly and encircles the an- terior ocellus; posterior ocelli smaller than the anterior oeellus? separated from the eyes by one and a half times their diameter, and from each other by twice their diam- eter ; latero-posterior margins of each posterior ocellus bor- dered by an impressed line which continues posteriorly in a medially concave curve to the vertical face of the occiput; genz (in lateral view) rather narrow, wider below. Man-



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19411 A New Stizus from Utah 173
dibles with a small tooth near the apex. Antennz long
enough to reach the posterior face of the propodeum; seg- ments 9-12 much shorter than the four preceding, 9 about Figure I.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figwe 6.
Figure 7.
Clypeus of Stizus iridis, sp. nov.
Clypeus of Stizus occidentalis Parker (holotype male). Eighth sternite of Stims iridis, sp. nov. Eighth sternite of Stizus occidemtalis Parker (holotype male).
Male genitalia of Stizus iridis, sp. nov. Sixth tergite of Stizus brevipennis$ lateral outline. Sixth tergite of Stim~s texanu, lateral outline, two-thirds as long as 8, 13 tapering to a round end and not emarginate within ; tyloids present as linear earinze on seg- ments 6-13, that on 5 very short, practically a tubercle.



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Thorax (in dorsal view) somewhat rectangular; prono- turn not elongate; parapsidal furrow8 not extended to the posterior margin of the m~soscutum, each represented by a slender carha with an extremely fine longitudinal impreg- sim; sutures defining the propodeal area strmg1y im- pregsed ; mao-metapleural suture sinuous, but not stmngly curved anteriorly; hind angles of the propodeurn tumid, Fore wings 17-18 mm. long, about four times as long a# the di~tance between the posterior lateral angles of the mem- scutum, the first transveme cubital vein pxactial!y straight. Legs slender,
Abdomen large and elongate; first tergik with a flattened anterior face, in dorsal aspect roundly angdate anteriorly, the concave ~ide~ (a8 seen from above) parallel towards the base, diverging posteriorly.
The puncturation is fairly coarse and dense over most of the body. The dypeus and supxaclypeal area, however, axe very finely punctate, and anterior to the black band acrw the vertex axe two areas with coarse, well-separated punc- tuxes.
The pubescence is pale and generally distributed, but longer, or at least more conspicuous, on the posterior half of the clypeus, the sides of the supraclypeal area, the anterior portion of the supra-antenna1 area, the vertex and the adja- cent occiput, the lower portion of the gem, the lower pm- tion of the mesap~euxa, the mesosternurn, the posterior
angle8 of the propodeurn, and the first tergite. Fed*- Unknown.
Types.-Holotype, Museum of Comparative Zdogy, Cambridge, No, 23397, One paratype, U. S. National Mu- seum, No. 55828. One paratype in the author's collecti~n. Type 10culity.- Rainbow Bridge National Manument, San Juan County, Utah.
Dist&but&m- Holotype male and two male paratypes taken at the type local$@, July 16, 1935, by Profemor C. T. Erues, who kindly supplied the following notes. "The specimens of the new Stizw were collected in the canyon about half a mile above Rainbow Natural Bridge near the camp established for visitors. Close t~ the open space in which the camp is ~ituakd are cliffs that form one



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19411 A New Stizm from Utah 175
of the cavelike hollows characteristic of the red sandstone of this region. In the early morning, over the steep talus slope to one side of this 'cave,' still in the shadow of the high cliff on the east, great numbers of these wasps were circling and darting about. In their erratic flight they would scarce- ly ever pause, and it was only after considerable effort that 1 finally secured three specimens. They did not appear at all wary and had it not been for the very insecure nature of the steep slope and loose rocks, they would have been taken quite easily. The wasps soon disappeared, long before any sunshine reached the spot. There was practically no vege- tation on the slope where the wasps were observed." Remarks.- The present species of Stizus is the fourth of the genus (as now restricted) to be described from North America. Of the remaining three it is most closely related to occidentalis Parker, a member of the ruficornis group. The male of the new species, like that of occidentalis, has the first transverse cubital vein practically straight, not evenly curved toward the apex of the wing. If the female should prove to have a scutellar pit (as it does in occidentalis), iridis may be assigned to the ruficornis group without question.
The types of iridis have been compared with the holotype male of occidentalis, which differs in the following struc- tural details. In the holotype of ~~ccidentalis the elypeus is evenly convex in profile; it has a wider emargination an- teriorly and the posterior margin is practically straight (fig. 2). Lateral to each posterior ocellus of the holotype of occidentalis, there is a longitudinal lshining impression, about one-third the diameter of the ocellus in width; it ex- tends posteriorly for a distance about equal to the diameter of the ocellus, but does not descend the vertical face of the occiput. Behind the anterior ocelhs there is no circular impression. Linear tyloids are present on antenna1 seg- ments 7-13, instead of 6-13 as in iridis; on the right antenna they are all conspicuous, but on the left less so, particularly on 7 and 8. In dorsal aspect the thorax appears more rounded anteriorly9 and more pointed behind. The parap- sidal furrows are represented by simple impressed lines- The posterior angles of the propodeum are less convex than in iridis, and the sutures defining the propodeal area are not



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176 Psyche [December
strongly impressed. The first tergite is distinctly rounded in dorsal aspect, and has a less sharply marked anterior face. Other &ruetural differences occur in the eighth sternite (figs. 3 and 4) and the parameres of the genitalia (compare fig. 5 with Parker's fig. 29).
The author discovered another genitalic character while comparing his paratype of iridis with two males of occi- dentalis kindly loaned by Dr. C. D. Michener. In occidentalis the compressed shaft of the digitus, when viewed laterally, is rather uniform in width, but in iridis its ventral margin is strongly emarginate.
Stizus occidentalis Parker
1929. Stizus occidentalis Parker, Proe. U. S. Nat. Mus. 75 (5) : 9, pl. 4, fig. 29. 8, 9.
This species was described from two specimens: a male from "San Diego County," California, collected by Coquillett, and a female from Florence, Arizona. As a result of the present author's recent trip to California, six additional specimens were located in various collections. This mate- rial, which considerably extends the known range, indicates that occidentalis is a desert species of the Lower Austral Region, and suggests that the holotype collected by Coquillett may really have been taken in what is now Imperial County, formerly the eastern part of San Diego County. CALIFORNIA :
Panamint Mts., Inyo Co. ; May '29, 1937 ; N. W. Frazier, I 8 [California Academy of Sciences]. Wild Rose Canyon, Panarnint Mts., Inyo Co. ; elevation, 3000 ft. ; flying about flowers of Prosop& chilensis in noonday sun- light; May 28, 1937; C. D. Michener ; 2 8, I ? [C. D.
Michener] . Furnace Creek, Death Valley ; on Pluchea seri- ma; May 1, 1927; P. H. Timberlake; I
? [University of
California Citrus Experiment Station]. Eight miles south of Needles ; on Acacia greggii; June 4, 1938 ; P. H. Timber- lake; I ? [University of California Citrus Experiment Station].
Stizus brevipennis Walsh
1869. Stizus brevipennis Walsh, Amer. Entomologist 1: 162. 8.




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19411 A New Stizus from Utah 177
1875. Lama byendeli Taschenberg, Zeitsehr. f. d. Ges. Naturwiss. 45 : 361.
8 .
1879. Megastizus brevipennis Patton, Bull. U. S. Geol. Survey Terr. 5: 345.
8, 9 .
1887. Megastizus brevipennis Cresson (pars), Synopsis : 278.
1892. Stizw brevipennis Handlirsch, Sitz. Akad. Wiss. Wien, Math.-nat. Cl., 101 (I) : 174, pl. I, fig. 13, pl. 2, fig.28, pl.3,fig. 15. 8, ?.
1895.
Stizus brevipennis Fox, Proc. Acad. Nat. Sci. Phila- delphia 1895: 266-268. 8 , 9 .
1941. Megastizus brevipennis Snodgrass, Smiths. Misc. Coll. 99 (14) : pl. 19, figs. A-G.
8.
The only published information relative to the prey of the North American species of Stims is a brief note by F. X. Williams (1913, Kansas Univ. Sci. Bull. 8 (4) : 198) to the effect that brevipennis "hunts in a manner quite similar to [Tachgtes] mandibularis, examining the stems of Helian- thm, etc., as she flies and finally finds her prey, a large Xiphidium." Dr. Williams has informed the author (in litt.) that the grasshopper in question is "a large short- winged adult ? of Xiphidium, now known as Conocephalus. It has a long, rather straight, ovipositor." In the selection of Orthoptera as prey, brevipennis agrees with the Old World species of Stizus, which, with two doubtful exceptions, have thus far been reported to capture either grasshoppers or mantids.
The male of brevipennis is very distinct from that of texanus. Besides the characters given in the accompany- ing key, the genitalia are entirely different. The females
of these [species are less readily distinguished, and as the pygidial character given by W. J. Fox does not appear to be valid, the present author has substituted another char- acter of the sixth tergite which is quite satisfactory. In the following list of specimens examined by the author, the record for Indian Head, Maryland, is by far the most surprising. It would certainly appear to be in error were it not for the occurrence of the species in central Florida. FLORIDA: Cape Barrancas; C. Willard; I 9 [M.C.Z.].



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178 Psyche [December
Gainesvilie; July 7 to 22, 1918; P. W. F'attig; 5 8 [U.S.N.M.] .
ILLINOIS: 2 8 [A.M.N.H.].
IOWA: Mount Pleasant; July 1920; I 9 [U.S.N.M.]. KANSAS : I 9 [U.S.N.M.]. Douglas Co. ; 900 ft. ; F. H. Snow ; I 8 [U.S.N.M.] . Riley Co. ; July 9 and 31 ; Popenoe ; I 9 and I 8 [U.S.N.M.]. Dickinson Co. ; August; Brid- well; 1 Q [U.S.N.M.]. Wellington; H. R. Watts; 1 Q [U.S.N.M.] .
MARYLAND : Indian Head ; August 23, 1902 ; Bridwell; I 8 [U.S.N.M.].
MISSOURI : St. Louis ; July 1911 ; P. Rau ; I 9 [U.S.N.M.] . N~BRASKA: Cambridge; July 26, 1921, August 2, 1921, and August 22, 1923; A. P. Morse; I
9, 1 8 [M.C.Z.], and
I 8 [Richard Dow].
OKLAHOMA: Ardmore; July 11, and August 18, 1905; C. R. Jones; I 8 and I Q [U.S.N.M.].
SOUTH DAKOTA: Springfield; August 27, 1926; H. C. Severin; I 8 [M.C.Z.].
TEXAS : Belfrage [collector] ; I 8 , I Q [U.S.N.M.] . San ) Antonio ; H. B. Parks; I 8 [U.S.N.M.]. WISCONSIN : Milwaukee ; August 12,1907 ; S. Graenicher ; I 8 [M.C.Z.].
Stizus texanus Cresson
1872.
Stizm texanus Cresson, Trans. Am. Ent. Soc. 4: 222. 8, 9.
1879.
Megastizus texanw Patton, Bull* U. S. Geol. Survey Terr. 5 : 345.
8, Q .
1887. Megastizus brevipennis Cresson (pars), Synopsis : 278.
1892.
Stizus texanm Handlirsch, Sitz. Akad. Wiss. Wien, Math.-nat. Cl., I01 (I) : 176, pl. I, figs. 6, 14, 15, pl.2;fig.29,p1.3,fig.l6. 8, Q.
1895. Stizus texunus Fox, Proc. Acad. Nat. Sci. Phila- delphia 1895: 267-268.
8, Q .
In the American Museum of Natural History there is a female of texanm from Tucson, Arizona, a locality con-



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. 19411 A New Stizus from Utah. 179
siderably west of the previously known range of the species. Though the head and thorax are normal in coloration, the abdomen is remarkable for the extent of the yellow macula- tions.
Whereas the lateral spots on tergites 3 and 4 are usually well separated in texanus, in this specimen they are united medially to form broad continuous fasci~, the first of which is deeply emarginate anteriorly7 but the second less so. There is also a broad fascia on tergite 5 which covers most of the exposed portion of the sclerite. Even the yellow spots on sternites 2, 3, and 4 are exceptionally large.
The following records are of specimens examined by the author.
ARIZONA : Tucson ; "Creosote bush assn." ; August 6, 1906 ; G. von Krockow ; I [A.M.N.H.].
TEXAS: 2 8 [M.C.Z.]. Lincecum [collector] ; 1 9 [M.C.Z.] . Alpine ; June 4, 1927 [?I ; I 8 [U.S.N.M.] . Cotulla ; June 21, 1906 ; H. Caley ; I 8 4 9 [U.S.N.M.] . "Dallas" ; Boll ; 9 8 , 9 9
[M.C.Z.] ad I 8 [Richard Dow] .
Laredo ; May 16,1924 ; 2 9
[U.S.N.M.] . San Antonio : May
27, 1937; 3 8 [U.S.N.M.].
In the following key to the known forms of Stizus occur- ring in North America, the author is following the division of the Stizini proposed by J. B. Parker in 1929 (Proc. U. S. Nat. Mus. 75
(5) : 7-11). According to this classification, Stizm unicinctus Say belongs in the genus StizoTdes (equiva- lent to the tridentatus group of Handlirsch, Berland, and Arnold), and the genus Bembecinw includes the forms with a concave propodeum. The name Megastizus is applicable to Stizus brewipennis and texanus, but whether these species form a group worthy of subgeneric rank is a question the author prefers to leave undecided until he has studied more material from other regions.
I. Males .............................................................................. 2. Females .......................................................................... 5. 2. Antennz without longitudinal carin~ on segments 9 and 10. Seventh tergite with large ventral lobes .......... 3. Antennz with Iongitudinal carinz on segments 9 and 10. Seventh tergite without large ventral lobes .......... 4.




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180 Psyche [December
3. Anterior margin of clypeus laterally with blunt teeth, its shallow nearly straight emargination with two low projections. Narrowed apex of seventh tergite broad- ly rounded; ventral lobes of seventh tergite broad, about twice as long as wide, broadly triangular at apex. Apex of seventh sternite broadly triangular, the more heavily sclerotized portion spear-shaped. Median spine of eighth sternite borne on a spear- shaped projection much narrower than the basal portion .............................................. brevipennis Walsh Anterior margin of clypeus evenly rounded. Apex of
seventh tergite narrowed into a flattened truncate pro- jection with a small but distinct median ernargination ; ventral lobes of seventh tergite slender, nearly three times as long as wide, narrowly triangular at apex. Seventh sternite narrowly triangular, truncate at apex, the more heavily sclerotized portion of similar shape. M,edian spine of eighth sternite on a broad triangular projection ........................... .texanus Cress. 4. Posterior margin of clypeus practically straight. An- tennal segments 7-13 with distinct tyloids. Sides of first tergite (in dorsal view) slightly convex. Thorax eonspicuous1y hairy. Mesopleura, metapleura, and .......................... propodeum mostly or entirely bIack .......................................................... ..occidentalis Parker Posterior margin of clypeus emarginate. Antenna1 segments 6-13 with distinct tyloids. Sides of first tergite (in , dorsal view) concave. Thorax not con- spicuously hairy. Mesopleura, metapleura, and pro- ................ podeum almost entirely yellow iridis, sp. nov.
5. Sixth tergite with a pygidial area ................................ 6. Sixth tergite without a pygidial area defined by lateral ridges. Posterior margin of clypeus practically straight. Lateral margins of first tergite slightly convex. Thorax conspicuously hairy. Mesopleura, metapleura, and propodeum mostly or entirely black ............................................................ occidental& Parker



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19411 A New Stizus from Utah 181
6. Anterior margin of clypeus with a broadly V-shaped emargination. Lateral margins of sixth tergite strongly sinuous (fig. 6) .................. brmipennis Walsh Anterior margin of clypeus with a shallow rounded emargination. Lateral margins of sixth tergite with ........ the basal three-quarters nearly straight (fig. 7) texanus Cress.
.................................................................... Acknowledgments.- The author is much obliged to the numerous entomologists and museums whose material he has been permitted to study, and especially to Professor Brues for the privilege of describing the new species and permission to retain one of the paratypes. For assistance in the preparation of this paper, he is greatly indebted to the late Miss Grace A. Sandhouse and to Mr. Karl V. Krombein, both of the Bureau of Entomology and Plant Quarantine.




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