J. A. Hyslop.
Observations on the Life-history of Meracantha contracta.
Psyche 22:44-48, 1915.

Full text (searchable PDF, 1316K)
Durable link: http://psyche.entclub.org/22/22-044.html

The following unprocessed text is extracted from the PDF file, and is likely to be both incomplete and full of errors. Please consult the PDF file for the complete article.

44 Psyche [April
OBSERVATIONS ON THE LIFE HISTORY OF MERA- CANTHA CONTRACTA (BEAUV).
BY J. A. HYSLOP,
Bureau of ~ntomolo~~, Washington, D. C.
Early in the spring of 1913, while searching for the larvae of Trichophorus (Ludius Latr.) about the bases of very much decayed stumps on the top of the South Mountain Range near Wolfsville, Md., I found many of the oddly shaped larvse of this beetle. This larva is very unique, being the only North American Tenebrionid with the ninth abdominal segment so formed. Candhze figures
a very similar larva, which he determines as the larva of' Tenebrion sp., from Ceylon which, he states, lives under sod. The species is very common and the larva has been recognized since 1849 when S. S. Haldeman briefly but lucidly described it under the name Physocoelus inflatus Dej. which name he later referred to synonomy under Helops contractus (Beauv.). An editorial note in the American Entomologist refers to this larva as being found in the stomach of a bluebird.
More recently, H. F. Wickham
has given a much more detailed description with several figures of this larva.
Larva: (PI. 4, Figs. a-j.)
The body is elongate, cylindrical; tegument highly chitinized, very sparsely beset with long fine yellow hairs; color reddish brown, paler ventrally and posterior margins of segments darker. Head globular, bent
downward, mouth directed forward and downward; a pair of large inconspicuous ocelli near base of antennae; front convex, finely and sparsely punctate, exterior angles produced into broad lateral lobes to antenna1 area, frontal sutures strongly curved outward; epicranial suture moderately long. Post-labrum transversely oblong, distinct and slightly produced, post labial suture pronounced, anterior and posterior margins parallel,
anterior third membranous. Labrum distinct, semicircular in outline, anterior edge slightly truncate and beset with strong bristles. Mandibles (Figs. d, f, g) stout but not exceptionally long, trifaced pyramidal; outer face convex with a convex disc shaped area impressed on basal half, a few slight transverse sulci, and a strong bristle near middle beyond impressed 1 Histoire des Metamorphoses de quelques Coleoptires Exotiques, p. 79, pi. V1,fig. 11 and lla. 2 Proc. Amer. Assn. Adv. Sci., Vol. 11, p. 347. 1849. 3 Proc. Acad. Nat. Sci. Philadelphia, V, p. 5, 1850. 4 Amer. Ent., Vol. 111, p. 201.
1880.
6 Journ. New York Eat. Soc., IV, p. 119-121. 8 This term was first used by Lyonet in his "Traite anatomique de la Chenille qui ronge le Bois de Saule. A la Haye, ed. 2, 1862," and seems very appropriate. Pu&e 22:44-49 ( 1915). hup Ytpsychu einclub nrgt22/22-044 html



================================================================================

area; dorsal face slightly concave; inner face concave with three stout blunt teeth on dorsal edge KÌö one similar tooth on ventral edge, these teeth are all beyond the out& third of the mftndible; molar area (Fig. d, 1) strongly produced, obliquely quadrate and concave, with outer ventral edge drawn out into a stout tooth, mncfive surface transversely carinate. Gula (̤ 11) trapeiriform; submenturn (e, S) broad, hexagonal; mentum (e, 3) traperiform with narrower edge directed posteriorly, as long as submenturn but narrower and bearing a pair of brisklea at he; labium (e, 1) roughly pentagonal smaller than mentum; ligula pronounced and armed with a pair of short spines; labial stipes (e, 10) moderately large; labial palpi (e, 9) two jointed, joint one short and broader than long, joint two equal in length to one but only as wide as long. Maxillae large; articulating membrane (e, 4) between submenturn wad cardo 3lighd~ chitid, quite h t ~ , cardo (e, 5), large, triangular; maxillary stipes (e, 6) large; maxillary palpi (e, 8) three jointed; lacinea (e, 7) broad and armed with two rows of b d short spines. Hypcpharyn- &I cbitinization (Fig. b) tricuspid, with surface concave, highly chitiiuzed. Anten- nas (Fig. c) situated at base of mandibles, three jointed, basal membrane large protuberant slightly chitmized, joint one nearly as broad as long slightly widened distully, joint two clavate, twice as long as wide, s~irmouated with a cushion like membranous cop on which is situated a small disc like antefiiuti appendage and the small third joint; third joint less than one-fifth length of second joint, cylin- drical, one-third as wide as long, bears two small hiis; antenm slightly retractile. First thoracic segment a5 long as braad, anterior margin finely etriate; second about one-half as long as first and third a little longer than second- legs (Fig. i) moderately long, coxa as long as femora and trochanter taken together, scoop ehuped with concave membranous surface to receive femora when in repose, edges of this surface beset with. hairs; trochanter large, triangular and serving as a support for femora, over the inner two-thirds of which it is prolonged; femora stout and short; tibia equal to femora in length but more slender; tarsus unguiform, in 1-li almost equal to tibia; femora and tibia with stoat spines on inner edge. Mestithorftcic spiracle oval and twice as long as the abdominal spiracles. Ten abdominal segments, one to eight about equal in diameter and length, posterior borders strongly deft exed but not striate, dorsal surface sparsely ~d finely punctate and slightly transverse-rugose, rugosity becoming more pronounced and pimcta- tion more dense and coarse caudad; ninth abdominal segment (Fig. j) obliquely truncate, truncate surface strongly concave' with acute margins; tenth abdominal' seginent (Fig. h) in small semi-circular orifice on basal quarter of venter of ninth abdominal segment and bearing two mammiform papihe. Spiracutar area of segments one to eight (Fig. h) oblong, with smd almost circular spiracles on anterior dorsal margin. Length 37 mm.
The nidus in which I found these larvae was composed of deep leaf mould and decayed wood. They seemed very sensitive to light and very rapidly burrowed away when unearthed. Several were collected and placed in rearing cages. Three days later (May 6) three of the larvse had pupated. The last larval exuvia were preserved for future identification of this species of larva.



================================================================================

46 Psyche [April
Pupa: (Fig. I.) Free: arcuate; cream colored with ferrugineous tinge on prono- turn; femora, tibia, head, and tarsi fuscate. Just before emerging the pupa becomes
much more strongly colored. Head bent strongly venterad; maxillary palpi very prominent, securiform; eyes almost black. Tips of wing cases extend slightly
beyond the anterior margin of second abdominal segment. Metatarsi almost
attain posterior margin of fifth abdominal segment. Posterior margin of meta-
no turn bears a pair of highly chitinized black securiform protuberances which are opposed by a pair of. black, chitinized, concave, areas on the anterior margins of the first abdominal segment. First to fifth abdominal segments bearing on sides Fig. 1. Merueantha contracts . Pupa.
of tergites two-lobed protuberances, lobes pointed and anterior one directed up- ward on first to third segment; sixth segment bears a one-lobed protuberance; seventh segment small, and very narrow dorsally; eighth segment ending in a pair of slightly divergent simply pointed processes. Dorsal surface of eighth
segment slightly concave.
Length 15 mm.
A fourth individual was about half transformed to a pupa when it was attacked and killed by the larva of a Coleopteron that I have not had determined. The predaceous larva was white in color and very much flattened dorso ventrally, and was placed in



================================================================================

19151 Hyslop-Meracantha contracta {Beam.) 47 the cage with the Meracantha while collecting. It killed its host
by eating into the thorax. Two weeks after pupation the first adult emerged.
When first transformed it was quite uniformly cream white; the legs and pronotum soon became infuscate, then brown and were followed by the elytra becoming darker. Finally
the entire beetle assumed the bronze black color of the mature imago.
One of the larvae that pupated on May 5 did not decay, as did the other pup% that failed to becomes beetles, and on June 14 a Bombyllid fly, Anthrax alternata Say.,l emerged from it. The pupa of this parasite is quite active just of the adult. It is provided with a row
of backwardly directed spines on the
dorsum of each abdominal segment, and
the dorsum of the terminal segment bears four stout spines and is terminated by a pair of prongs (Fig. lid). By alternately flexing the body forward and backward,
the spines preventing any backward move- ment of the sclerites, the pupa moves for- ward. It pushed off the prothorax and
head of its host pupa (Fig. IIc) and
protruded from the opening thus formed
(Fig. IIa) until the adult parasite emerged. The head capsule of Anthrax (Fig. IIb)
is armed with three pair of stout teeth
which probably assist in the act of emerg- ing from the host. The adult Anthrax
prior to the emergence
Fig. 2. Meracuntha contracta.
Pupal case and pupal case of
parasite, Anthrax alternata.
emerged from its chrysalis by forcing off the pupal head capsule and splitting the dorsum of the pronotum. How this parasite locates the larvae of Meracantha, which never come above ground as far as I have observed, where she oviposits, and the period the parasite spends within its host still remains to be determined. In August of the same year I again made observations on Meracantha contracta. On this occasion I was collecting the larvae of Sericosomus viridanus Say. from under the moss, Poly- ,
trichum ohioensis, on the top of the same mountain range but near 1 Determined by Mr. W. R. Walton.




================================================================================

48 Psyche [April
Myersville, Md.
Living Meracantha larvae were found though, from the cast larval skins and dead larvae, they must have been much more numerous earlier in the season. In four distinct cases I found the empty skins of the Tenebrionid larva with one or two Tachinid puparia close by. In every case, however, the parasites had emerged. A number of these puparia were collected and later observations proved them to be of a Neopales sp. n.l On November 21 I made my last trip to the mountains for that season. At the same spot, where I collected the Neopales puparia in August, I collected several larvae of Meracantha. The larvae were placed in rearing cages and passed the winter in this stage. On May 23, 1914, the cage was examined and one of these larvae was found to have pupated, the adult emerging six days later. Another larva pupated between May 25 and May 27, and from this pupa the adult emerged on June 5. From our observations we conclude that the pupal stage of this beetle endures from ten to fourteen days.
Two larvae from the same material were killed by Neopales and, on May 23, a parasite larva emerged from each host larva and pupated.
The adult Tachinid emerged on June 4, which limits the puparium stage to twelve days. This Tachinid must pass the winter within its host.
EXPLANATION OF PLATE 4.
Meracantha contracts (Beauv.), larva and details. Fig. a, Dorsal aspect.
b, Hypopharyngial chitinization.
c, Antennae.
d, Left mandible, inner face, 1, molar area. e, Labium and maxillus. 1, labium; 2, mentum; 3, submentum; 4, articular membrane between submentum and cardo; 5, cardo; 6, maxillary stipes; 7, lacinea; 8, maxillary palpus; 9, labial palpus; 10, labial stipes; 11, gula; 12, ligula. f, Left mandible, dorsal face.
g, Left mandible, outer face.
h, Seventh, eighth, ninth, and tenth abdominal segments, ventral aspect. i, Left mesothoracic leg.
j, Ninth abdominal segment, lateral aspect. 1 Determined by Mr. W. R. Walton.




================================================================================




================================================================================