Frank M. Carpenter.
The Structure and Relationships of Oliarces (Neuroptera).
Psyche 58(1):32-41, 1951.

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THE STRUCTURE AND RELATIONSHIPS
OF OLZARCES (NEUR0PTERA)l
BY FRANK M. CARPENTER
Harvard University
Somewhat more than forty years ago, Dr. John B. Smith, while traveling in California, collected a conspicuous neurop- terous insect, which was subsequently described by Banks (1908) as Oliames clwra. Efforts to find additional individ- uals were unsuccessful for many years, but a second speci- men has at last been secured. Mr. P. A. Adams, of the University of California, who received the insect from the collector and who has already published a note on its dis- covery (1950), kindly loaned me the new specimen for fur- ther study and for comparison with the type. I am indebted to him for this courtesy and for the opportunity of clarify- ing, to some extent, the systematic position of this remark- able insect.
The type locality, "Walters Sta., Calif.", has been the subject of much speculation and its location not generally known. According to Mr. Banks (personal communication) Smith collected the specimen while the train on which he was traveling was stopped at Walters Station for water. Current maps do not include this place, but the 1901 edition of the Century Atlas shows a "Walters" on the Southern Pacific Railroad, about ten miles northwest of the Salton Sea bed; and the engineering department of the Southern Pacific Company informs me that this was a station around 1900. It is also listed in Gannett's "Dictionary of Altitudes" (1906), which further states that the "point on base under water tank" is 191 feet below sea level. There is no doubt in my mind, therefore, that this Walters is the type locality of Clara. The new specimen was collected near Parker Dam, San Bernardino County, about 70 miles from Walters and in the same kind of environment.
Published with the aid of a grant from the Museum of Comparative Zoology at Harvard College.
32
Pache 58:32-41 (1951). hup //psyche einclub nrgtS8158-032 html



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19511
Carpenter - Qliarces 33
The following account of the structure of Oliarces clara is based on the holotype (male) and the new specimen (fe- male), which is here designated the allotype : Frons and vertex dark brown to black; clypeus, mouth- parts and antennae light reddish brown; pronotum and mesonotum dark brown to black; metanotum dark reddish brown, lighter near wing bases; legs yellow-gray to medium brown ; abdominal termites medium brown, membranous areas yellow-brown ; last two abdominal segments dark red- dish brown above; abdomen yellow from beneath. Wings hyaline, the bases tinted with reddish brown. Antennae (broken away at second segment in holotype) with 40 sub- equal segments. Body in general covered with long brown or black hairs. Fore wing of holotype 16 mm. long and 5 mm. wide (maximum) ; that of allotype 20 mm. long and 7 mm. wide. Both pairs of wings are of similar texture, being color- less and hyaline. Each wing bears two distinct nygmata. The wing venation of the allotype is shown in text-figure 2; that of the holotype has already been figured by Banks (1908). As Adams has pointed out, the venational differ- ences in the wings of the two specimens are well within the limits of variation occurring in other Neuroptera. A dis- cussion of the generic features of the venation is included below.
The terminal abdominal segments of the male, briefly des- cribed by Banks, are illustrated here (Plate 4, fig. 2) in detail because of their significance in determining generic relationships. The ninth tergite is much longer laterally than dorsally, being reduced to a narrow strip in the mid- dorsal region. The ninth sternite has migrated posteriorly so that it is ventral to the tenth tergite; it is long laterally but constricted medially. The tenth tergite is conspicuously extended to form the anal plates, which are directed more dorsally than ventrally and which appear from above like hairy knobs. A posterior-dorsal view of the abdomen clearly shows the anus, as well as a pair of sclerotized structures which are apparently the modified tenth sternite. The terminal segments of the female abdomen are shown in figure 3B, drawn from Mr. Adams' specimen. Although



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34 Psyche [March
these were not removed and softened, as was done with the holotype, the sclerites are clearly defined. The eighth tergite extends further ventrally than the preceding tergites, and the ninth extends to the ventral surface. The eighth sternite is not visible externally, but is presumably reduced to scler- otized rods or plates encompassed by the ninth tergite. The tenth tergite is small and tapering, with conspicuous trkho- bothria near the margin of the ninth tergite. The ninth sternite is represented by a pair of very small plates, more or less fused, each bearing a minute papilla distally. These two plates are apparently the homologues of the psammaro- trum or sand-plow of the Australian ithonids. Holotype ( 8 ) : Walters Station, California ; April (3. B. Smith) ; in M.C.Z.
Allotype (by present designation) : 3 mi. southwest of Parker Dam, San Bernardino Co., April 25, 1949 (C. M. MacNeill), taken at light; in collection of P. A. Adams. Since only one species of Oliarces is known, any diagnosis of the genus is probably tentative. However, considering the characteristics involved in the classification of other Neuroptera, I propose the following: the hyaline nature of both pairs of wings; in the fore wing the presence of a re- current costal vein, of about five (probably variable) bran- ches of Rs, and of relatively few cross-veins in the wing as a whole, as well as the absence of connecting cross-veins be- tween costal veinlets; in the hind wing the transverse posi- tion of the basal part of MA (see below) ; in the male ab- domen, the dorsally directed anal plates; and in the female; the absence of a distinct psammarotrum. The presence of two nygmata in the hind wing is of doubtful generic value, although only one is present in the specimens which I have seen of Ithone, Heterithone and VamW,.
The relationships of Oliarces with other Neuroptera have been very uncertain. Although originally placed by Banks (1908, 1913) in the family Hemerobiidae, as broadly con- ceived, it does not fit into the current and more restricted definition of that family, Tillyard, who noted this in 1916, suggested that a new family might be needed for it, but did not formally establish one. On the other hand, Brues and



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1951 I Carpenter - Oliarces 35
Melander (1932) listed the genus under the family Ith- onidae, otherwise known only from Australia; and Lameere (1936) has placed it in the Polystoechotidae. Since the un- certainty of the systematic position of OZZCLrces has been due in part to our very limited knowledge of the species on which it was baaed, the discovery of the female has given us addi- tional information useful in comparisons. It is at once clear, of course, that several superfamilies (Tillyard, 1925) of the Neuroptera-specifically the Con- iopterygoidea, Nernopteroidea and Myrmeteontoidea - are so far removed structurally from Oliarces 'as to be elimh- ated from further consideration. The superfamily Hemero- bioidea is not so readily disposed of, but many of the in- cluded families (i.e., Dilaridae and Mantispidae) can have only the remotest affinities with Oliarces. The Osmylidae, although superficially resembling' Olwrces more than most hemerobioids, have a radically different abdominal struc- ture, as can be seen by comparing Killington's figures of Osmylus (1936, p. 56 and 58) with those of Oliarces in the present paper. The Polystoechotidae, to which Lameere as- signed Oliwces, and which were reviewed in my 1940 re- vision, have wings with definite gradate veins, absent in Olwrces ; and the terminal abdominal segments (Carpenter, 1940, figs. 70 and 72) of both sexes bear no resemblance to those of Oliarces, there being no anal plates in the male and no indication of a psammarotrum in the female. The Heme- robiidae, being a much larger and diversified family than the Osmylidae and Polystoechotidae, exhibit a greater range of structural differences (Killington, 1936-37 ; Carpenter, 1940). In all, however, there are gradate veins and a vena- tional pattern basically unlike that of Oliarces. The term- inal abdominal segments of the males of some genera are surprisingly suggestive of those of Oliarces, but this is not true of the females.
I have passed over these hemerobioid families very briefly because I believe that anyone who examines the specimens of Oliarces or studies the figures included here will not seriously consider assigning the genus to any of them. The family Ithonidae, however, deserves much more detailed



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36 Psyche [March
consideration. As now known, it consists of three Australian genera : Rhone (New South Wales) with one species ; Het- erithone (eastern Australia) with three species ; and Var- nia (central and Western Australia) with a single specie^.^ Ithone is the only one of these that has been collected in large numbers, the others being known by very few individ- uals. Specimens of all of these genera are contained in the Museum of Comparative Zoology, and have been studied for the present paper. Since no detailed drawings have been published showing the arrangement of the terminal ab- Text-fig. 1. Ithone fusca Newman. Fore and hind wings of male specimen in M. C. Z. (Woy Woy, N. S. W., Nov. 4, 1918, R. J. T.). Rs, radial sector; MA. anterior media; MP, posterior media; b, basal piece of MA between MP and Rs.
do'minal sclerites in the Ithonidae, I include here a series of such drawings of Ithone fusca, and, to facilitate compar- ison with Oliarces, a drawing of the wings of the same species.
The monotypic genus Rapisma, from the Malay Peninsula, has been doubtfully referred to the Ithonidae by some workers, but was excluded from there by Tillyard (1916). It will be treated in another article.



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19511 Carpenter - Oliarces 37
In comparing the venation of these genera with that of Oliarees, I have found it helpful to use the interpretation of neuropterous venation that was originally proposed by Martynov and that I employed in my revision of the Nearctic Hemerobioidea (1940, pp. 193-194). According to this con- cept, the most anterior branch of the media (labeled MA) is anastomosed in part with the radial sector or its last branch. In the fore wing, the actual separation of MA from Text-fig. 2. Oliarces clara Banks. Fore and hind wings of allotype. Lettering as in texbfigure 1.
MP is not apparent, but in the hind wing the basal piece of MA may extend a considerable distance before coalescing with the radial sector.
Such is the case in Ithone (text-
figure I), Heterithone and Varnia. In Oliarees this segment of MA is very short and transverse, though it retains the sigmoidal form present in the Australian ithonids. This difference should not be regarded as more than of generic significance, however, since the several genera of Hemero- biidae exhibit a comparable diversity in the length of this segment. The same may also be said of the density of the



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38 Psyche [March
venation, for although there are fully twice as many term- inal branches in the ithonids as in Oliarees, such diversity likewise occurs within the Hemerobiidae. The general body structure of Oliarees, including the small, retracted head? and the large abdomen? strongly re- sembles that of the ithonids. The terminal abdominal seg- ments, however, present some interesting differences. In the male of Ithone, as well as of Heterithone and Va'rnia, the ninth abdominal tergite is entire dorsally9 even though much constricted (Plate 4? fig. IA). The ninth sternite (hypandrium of Tillyard's terminology) of these genera? as in nearly all Planipennia, is extended further posteriorly than the tergite? but it is not nearly so modified here as in most Neuroptera. The tenth tergite, which includes the trich- obothria? bears a pair of conspicuous anal plates? extend- ing posteriorly and slightly curved inwardly. The tenth sternite is apparently reduced to internal plates, as in nearly all other Neuroptera. The homologues of the sclerites are Text-fig. 3. A, Tkrminal abd~minal segments of f'emale of Ithone jusca Nzwrnan. Drawn from specimen in M, C. Z. (Woy Woy, N. S. W., Nov. 3, 1918, R. J. T.). Lettering as in text-figure 1. B, Terminal ab- dominal segments of female of Oliarces clara Banks. Drawn from allo- type. Lettering as in text-figure 1.
readily found in Oliarces. Its ninth tergite is more con- stricted medially than in Ithone, but it is still undivided. The ninth sternite has migrated further posteriorly, and is smaller than in Ithone, but is otherwise similar. The anal plates of the tenth tergite? though directed upwards instead



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of posteriorly, could easily be modifications of those of Ithone.
The terminal abdominal segments of the female of Ithm are shown in text-figure 3A. Tillyard, in describing these (1919, p. 426), states that the eighth, ninth and tenth ah- dorninal segments "are more or less fused together, form- ing the projecting end of the abdomen."
In aIcoholic speci-
men~, however, the segmenh are perfectly distinct. The eighth tergite extends further ventrally than the seventh; and the ninth, as in nearly a11 Planipennia, raches all the way to the ventral surface. The eighth sternite is not visible externdly. The ninth sternite in all the ithonids is posterior to the ninth tergite and is enlarged to form the sand-plow or paammarotrum. Its two lateral plates are fused dorsally by membranes but are, of course, separated posteriorly in the region of the gonopore. The psammarotrum bears a pair of con~picuous processes, directed ventrally ; these were thought by Tillyard to be used as tactile organs during ovi- position. The tenth tergite is short, hood-shaped and bar^ the trichobothria. In OZfarces (Figure 3B) the ninth tergite is not so long ventrally as in Ithoxe and the ninth stemite is reduced to a pair of very miall plates, scarcely extending beyond the tenth tergite.
That these plates do comprise the
ninth sternite is indicated by the presence of a pair of ~mdl distal papillae, which, although they project dor~ally, are clearly homologues of the longer, ventral processes in Ithom. No true psammarotrum~ comparable to that of Ithone, i~ formed, but the structure is there in reduced form. The tenth tergite of Olkrces is similar to that of Ifhone, exwpt fox a slight difference in its shape.
From the evidence reviewed above, Oliurces appears to be closer to the Australian ithonids than to any other Neu- xoptera. This resemblance is, in fact, so close that only one modification need be made of Tillyard's definition of the family; this is the recognition that the psammarotrum may be very small or vestigiaL2 It is noteworthy in this con- Tillyard also stated in his definition of the lthonidae that the fore wings were of tougher consistency than the hind, Wing samewhat leathery; but this is certainly not true of HeteritTmne patlida, which Tillyard himself described as having very transparent and cohwTe?s wings.




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40 Psyche [March
nection that the reduced psarnmarotrum
in Olia~ces and
many of its other features (e.g.? the short basal piece of MA in the hind wing) appear specialized as compared with the corresponding structures of the Australian ithonids. The inclusion of Olia~ces in the Ithonidae certainly makes an unusual distributional pattern for the family? but the paucity of specimens of most species implies that the group might well have a much wider distribution than is now known. Of course? since the larvae of the Neuroptera pro- vide the only completely satisfactory basis for their family classification, the systematic position of Oliarces will not be truly solved until its immature stages have been dis- covered.
REFERENCES CITED
ADAMS. P. A.
1950. Notes on Oliarces clara Banks. Pan-Pacific Ent., 26:137-138. BANKS, N.
1908. A new genus and species of Neuroptera. Ent. News, 19:203-204. BXUES, C. T. and A. L. MELANDER
1932. Clas~ification of insects. Bull. Mus. Comp. Zool. Harvard Coll., 73 : 1-672.
CARPENTER, F. M.
1940. Revision of the Neartic Hemerobiidae, Berothidae, Sisyridae, Polystoechotidae and Dilaridae. Proc. Amer. Acad. Arts Sci., 74 1193-280.
GANNETT, H.
1906. Dictionary of altitudes in the United States. U.S. Geol. Surv., Bull. 274 (Ser. F, geogr. 47) :I-1072.
KILLINGJON, F. J.
1936-37. Monograph of British Neuroptera. 2 vols. Ray SOC. LAMEEYE, A.
1936. Precis de Zoologie, 5 : 25-47.
M'LACHAN, R.
1886. A new genus of Hemerobiidae, and a new genus of Perlidae. Trans. Ent. SOC. Lond., (3) 5 (4) :353-354, TILLYARD, R. J.
1916. Studies in Auskalian Neuroptera. No. 4. The Families Ithonidae, Hemerobiidae, Sisyridae, Berothidae. Proc. Linn. SOC. N. S. Wales, 41 :27Q-332.
191: Studies in Australian Neuroptera. No. 8. Revision of thte Family Iihonidae. Pro:. Lmn. Soc. N. S. Wales, 441414-437. EXPLANATION OF PLATE 4
Fig. 1. Terminal abdominal segments of male of Ithone fusca Newman. Drawn from specimen in M. C. Z. Way Woy, N. S. W., Nov. 5, 1918, R. J. T.). lA, dorsal view; lB, lateral view; lC, ventral view; ap. anal plate; 8T, 9T, lOT, abdominal tergites; 8S, 953, abdominal sternites. Fig. 2. Terminal abdominal segments of male of Oliarces clara Banks. Drawn from holotype (M. C. Z.) . a, anus. Other lettering as in figure 1.



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