Spilman, T.J.

Proceedings of the Hawaiian Entomological Society

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Vol. XIX, No. 2, September, 1966 297Larva and Pupa of Amarygmus morio from Hawaii(COLEOPTERA: TeNEBRIONIDAE)T. J. Spilman1'2Larvae of a tenebrionid were found in a decayed mango tree trunk atHilo, Hawaii, by E. B. Fryer, 22, V, 53. Some were reared to pupaeand adult; then all three stages were sent to the U. S. National Museum.I have identified the adults as Amarygmus morio (F.). The immature stagesare described below for the first time.This species was reported twice from the Hawaiian Islands asAmarygmus near morio. Maehler (1952:367) reported that specimens werefound at Kuhio Wharf, Hilo, 1, XI. 51 in aerial prop-roots of pandanusand added that this might be the same as that taken at Pearl Harboron Oahu two years earlier. Swezey (1953:11) reported specimens foundnear the fruit fly insectary at Hilo, 22, VI. 52. Undoubtedly Amarygmusmorio was introduced accidentally into Hawaii. The species had beenreported previously from Australia, Tasmania, New Guinea, Ceram, Aru,New Britain, and New Ireland.THE LARVABody elongate, cylindrical, wireworm-like; length, 20-24 mm; surfaceshiny, strongly chitinized and pigmented, mostly yellow-brown; with afew long, slender setae on most body areas.Head is globular, bent downward (Fig. 1). Coarse, sparse punctures dorsally and laterally; small setae laterally on border just behindclypeus; long, sparse setae on lateral areas. Frontal sulcus with basal partof moderate length, then strongly bifurcating, each branch angled anteriorly,then again bifurcating with one branch to lateral area of clypeofrontal sutureand one branch to lateral border of head capsule just posterior to antenna.Eye spots paired on each side; dorsal spot larger than ventral and fartherfrom base of antenna. Clypeus smooth, impunctate, with 4 long setae.Labrum smooth,impunctate, length subequal to length of clypeus; with pairof widely separated, long setae on disc, anterior border with 2 shorter setaemedially and 3 long setae laterally. Labrum with ventral surface (Fig. 4)having anterior border with 4 long, coarse setae laterally and 2 coarse setaemedially, with papilla just lateral to base of each medial seta; centralarea with 3 rows of papillae, 2 in first row, 2 in second row, and 4 smallerpapillae in posterior row then in order posteriorly, with 2 widely spacedrows of dense, coarse, medioposteriorly directed setae, between which areEntomology Research Division, Agricultural Research Service, U.S. Departmentof Agriculture.2I thank Dr. Nodoka Hayashi of Yokohama, Japan, for providing larvae of Plesioph-thalmus nigrocyaneus for this study.298 Proceedings, Hawaiian Entomological Society2 very coarse setae, then with a pair of raised, angulate, broad tormae,then with 2 longitudinal rows of very short, coarse, truncate setae lateralto 2 longitudinal rows of 8 small papillae. Mandible (Figs. 5, 6) withlateral surface rounded apically and with triangular excavation on basaltwo-thirds, with 1 seta on each corner of excavation; apex trifid, dorsaltooth more distinct on right mandible than on left; dorsal cutting edge without tooth; molar area large, protruding, with 3 heavy ridges. Maxilla(Fig. 3) with mala having 2 longitudinal rows of coarse, dense setae onmedial area and having dense, long, slender setae on dorsal surface; palpuswith apex of 2nd segment on level of apex of mala. Labium with ligulapronounced, digitiform; hypopharyngeal sclerome (Fig. 2) heavilysclerotized, projecting, with lateral borders divergent anteriorly, withmedial cusp broad and irregularly truncate, with surface transversly concave except for transverse carina near posterior border. Antenna (Fig. 9)with 1st segment without setae and two-thirds length of 2nd; 2nd withvery small setae on apical border, apex with large reniform, dinstinctlydelimited, white area; 3rd very small, styliform, with one long apicalseta and few very small setae on apical border.Body. Terga with small irregular wrinkles. (In the following,1st, 2nd, etc., refer to abdominal segments.) Prothoracic and 1st through7th with coarse, shallow punctures, these punctures on anterior bordersof anterior segments and gradually becoming more numerous and coveringa larger area on posterior segments. Prothoracic with anterior borderhaving 6 long, slender setae, with posterior border having 4 long, slendersetae placed laterally; mesothoracic, metathoracic, and 1st through 7thwith 6 long, slender setae on posterior border and 1 long, slender seta onanterolateral corner. Mesothoracic, metathoracic, and 1st through 8thwith indistinct longitudinal lateral line becoming slightly more obvious onposterior segments and with dark, weakly curved, clavate fascia just dorsalto lateral line. Spiracles elliptical, obliquely placed with ventral end directed slightly posteriorly. The 9th (Fig. 10) with deep concavity dorsally,its border transverse anteriorly and arcuate laterally and posteriorly, with4 small, blunt teeth posteriorly; concavity with weak convexity medio-anteriorly, with dense, coarse punctures except medially; ventrally convexwith long, sparse, slender setae and with dense, coarse punctures antero-laterally. Sterna impunctate, weakly pigmented; 1st through 8th withanterior and posterior transverse rows of long, slender setae, lateral setain each posterior row longer than others; 1st with 4 setae in both rows;2nd through 7th with 2 in anterior row, each laterally placed, and 4 inposterior row, each pair laterally placed; 8th with 2 in anterior row, eachlaterally placed and 5 in posterior row, all equally spaced; 9th formingflap-like operculum, with a few short, slender setae; posterior opening with2 distinct papillae, each posteriorly sclerotized and with small setae.Legs. Sparsely setose; not modified for digging; prothoracic onlyVol. XIX, No. 2, September, 1966 299Figs. 1-11. Amarygmus morio; 1-10, larva; 11, pupa. 1, head capsule, dorsalview. 2, hypopharyngeal sclerome, dorsal view. 3, left maxilla, dorsal view. 4,labrum, ventral view. 5, left mandible, dorsal view. 6, right mandible, dorsalview. 7, antenna. 8, left prothoracic leg, posterior view. 9, left mesothoracicleg, posterior view. 10, 9th abdominal tergum, dorsal view. 11, whole pupa,dorsal view.300 Proceedings, Hawaiian Entomological Societyslightly stouter than others and its setae slightly coarser (Figs. 7, 8). Coxaewith long, slender setae on anterior and posterior dorsal borders. Tro-chanters with 2 short setae on ventral surface. Profemur with 2 short,coarse setae and 1 long, slender seta on ventral surface. Protibiotarsus with3 short, coarse setae on ventral surface, and 1 short, coarse seta on posteriorsurface. Mesofemur and metafemur with 2 short, coarse setae and 1 long,slender seta on ventral surface, and 2 short, coarse setae on posterior surface.Mesotibiotarsus and metatibiotarsus with 4 short, coarse setae on ventralsurface, and 2 short, coarse, setae on posterior surface. Claws with 2short ventral setae.This larva is similar to two other described tenebrionid larvae:Plesiophthalmus nigrocyaneus Motschulsky from Japan, described by Fukuda,Kurosa, and Hayashi (1959:485, figs.), and Meracantha contracta (Palisot)from the United States, described by Wickham (1896:119, pi. 4, fig. 2) andHyslop (1915:44, pi. 4, figs. a-j). The three larvae are most easily separated by counting the coarse setae on the legs. In the following tabulationthe numbers of coarse setae on the ventral and posterior surfaces are separated by hyphens for the profemur, protibiotarsus, mesofemur and metafemur,and mesotibiotarsus and metatibiotarsus, in that order, for each species:Amarygmus morio, 2—0, 3—1, 2—2, 4—2; Plesiophthalmus nigrocyaneus, 2—2,3—5, 3—2, 3—7; Meracantha contracta, 2—2, 2—3, 2—2, 2—4. In addition, the larvae of the last two species differ from the larva of the first in thefollowing ways: Setae, punctures, and pigmentation stronger and coarseroverall; labrum with ventral surface having papillae near anterior bordercloser to long lateral setae than to medial setae, having central area with4 papillae in anterior row, 2 in medial row, and 4 smaller papillae in posterior row, and having large, arcuate, coarse transverse torma just anteriorto usual pair of arcuate tormae; concavity of 9th tergum with surfaceevenly concave, with anterior border arcuate and with posterior borderhaving blunt teeth absent or minute.It is obvious from these comparisons that the larvae of Meracanthacontracta and Plesiophthalmus nigrocyaneus have much more in common thandoes either with Amarygmus morio; this seems paradoxical because the firstis placed in the tribe Meracanthini and the second and third in the tribeAmarygmini. However, those tribes were established more than 100years ago when evidence from larvae was not included in the classificationand when adult morphological characteristics were used that today wouldprobably be given only generic rank.THE PUPAWithout obvious setae; posterior segments with a few minute setae(Fig. 11).Pronotum. Similar in shape to adult pronotum. Lateral border withapproximately 25 very short tubercles; these, more numerous posteriorly.Vol. XIX, No. 2, September, 1966 301Abdomen. Terga broad, most with lateral processes which projectlaterally on posterior segments and more dorsally on anterior segments.The 1st with posterior border near lateral corner having broad, truncate,heavily sclerotized lobe forming anterior border of gin trap. 2nd withanterior border near lateral corner having weakly incurved, sharp, heavilysclerotized edge forming posterior border of gin trap. Lateral process of2nd with 2 projections, the anterior broad with apical spinous seta andconverging posteriorly to posterior projection, the converging bordernot smooth; posterior projection, with apical spinous seta and with roughposterior border. Lateral processes of 3rd through 6th like that of 2nd except anterior projection is large tubercle. Lateral process of 7th broad,with long spinous seta. 8th without lateral process, with short ventrallydirected spine. 9th with pair of long, acute, diverging urogomphi, eachwith small spine laterally.As in larvae, the pupa of Meracantha contracta, described by Hyslop(1915:46, Fig. 1), is similar to the pupa of Amarygmus morio. However,the former has the following abdominal characteristics not present in thelatter: All lateral processes blunter; 7th tergum evenly arcuate laterallyand without processes. The pupa of Plesiophthalmus nigrocyaneus has notbeen described and specimens are not available to me.LITERATURE CITEDFukuda, A., K. Kurosa, and N. Hayashi. 1959. Coleoptera, pp. 392-545, illus.In T. Esaki, T. Kawada, N. Yuasa, N. Ishii, and T. Motoki, editors, Illustratedinsect larvae of Japan. (In Japanese.) Hokuryukan Co., Ltd. Tokyo.,Hyslop, J. A. 1915. Observations on the life history of Meracantha contracta (Beauv.).Psyche 22 (2): 44-48, 2 figs., pi. 4.Maehler, K. L. 1952. A new tenebrionid beetle. Proc. Haw. Ent. Soc. 1951 (1952)14 (3): 367.Swezey, O. H. 1953. Amarygmus near morio (F.). Ibid. 1952 (1953) 15 (1): 11.Wickham, H. F. 1896. Description of the larvae of some heteromerous and rhyncho-phorus beetles. Jour. New York Ent. Soc. 4 (3): 118-124, pi. 4, figs. 1-6.

Larva and Pupa of Amarygmus morio from Hawaii (Coleoptera: Tenebrionidae)

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Larva and Pupa of Amarygmus morio from Hawaii (Coleoptera: Tenebrionidae)

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