Recent Advances in Insect Embryology in Japan and Poland
Edited by H. Ando and Cz. JuraArthropod. EmbryoL. Soc. Jpn.
(ISEBU Co. Ltd., Tsukuba) 1987

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Embryonic Development of the Corpora Allataof Papilionidae (Lepidoptera)

Masahiro T ANAKA
SynopsisEmbryonic development of the corpora allata of Parnassius glacialis, Luehdorfia japonica, Byasa(Atrophaneura) alcinous alcinous and Papilio machaon hippocrates is described. The origin and theformation of corpora allata are the same among these four species belonging to different genera
respectively. When the cephalo-gnathal appendages begin to arrange themselves around the stomodaeal opening, and the prothoracic glands are separated from the ectoderm before the revolution stage, the rudiments of corpora allata appear as a pair of ingrowths on the wall of theapodemes of flexor mandibulae. They are carried dorsally in close contact with the wall of
apodemes, and then they are cut off from it, coming finally to lie at the posterior part of the extremities of the transverse bridge of the tentorium, under the ventral side of the brain.

Introduction
Several observations on the embryonic development of corpora allata in the Lepidoptera have been done by Ito (1918), Eastham (1930), Okada (1960), Kobayashi(1983) and Kobayashi and Ando (1983). The origin of corpora allata and the mannerof their formation in the early stage of development are essentially the same in the lepidopteran embryos until now studied, but there are some differences of opinions concerning the later stage among the species or genera in the order.
In the present paper, the author describes the embryonic development of corpora
allata of Pamassius glacialis, Luehdorfia japonica, Byasa (Atrophaneura) alcinous alcinous andPapilio machaon hippocrates.

Materials and Methods
To obtain eggs for the study, pregnant females of Pamassius glacialis Butler,

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M. TanakaFigs. 1-4. Formation of the corpora allata in Byasa (Atrophaneura) alcinous alcinous.
1. Longitudinal section through the gnathal region of the embryo, at about 3 days after oviposition. 2. Cross section through the head region, at the somewhat laterstage as shown in Fig. I. 3. Cross section through the head region, shortly before
the revolution stage (at about 3.5 days after oviposition). 4. Cross section throughthe head region, at the embryonic moulting stage (at about 4.5 days after oviposition).
CA, corpora allata; BR, brain; BT, bridge of tentorium; FG, fore-gut; FM, flexor mandibulae; MA, madibular apodeme; MD, mandible; MEC, mesodermal cell; MX, maxilla; TE,tentorium; TR, trachea ..

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Luehdoifza japonica Leech, Byasa (Atrophaneura) alcinous alcinous Klug and Papilio machaon
hippocrates C. et R. Felder were captured at various parts in Gifu Prefecture in 1980 to1983. Freshly laid eggs of Par. glacialis were obtained in May, those of L. japonica inApril, those of B. (A.) alcinous alcinous in June and those of Pap. machaon hippocrates in
September and kept at room temperature in the laboratory.
The eggs at various ages were fixed in Carnoy's fluid for 30 - 40 min or alcoholic
Bouin's fluid for 60 min. After fixation, the eggs removed of their chorion were dehydrated and embedded in paraffin. Sections were cut in 8 p. m thick and stained withDelafield's haematoxylin and eosin.

Observations
At about 11 days after oviposition in Par. glacialis, about 7. 5 days in L. japonica,
about 3 days in B. (A.) alcinous alcinous and about 3 days in Pap. machaon hippocrates, theembryos decrease in length, owing to the remarkable shortening of the head region including the gnathal segments, but they increase in width. Then the cephalic and thegnathal regions fuse each other, and three ganglia in the gnathal segments unite toform a large single suboesophageal ganglion. The cephalo-gnathal appendages cometogether to form the mouthparts around the stomodaeal opening. The pro thoracic
glands are separated from the wall of the labial segment to be deposited at the anterior
margin of prothoracic segment. At this stage the mandibular apodeme at the lateroposterior part of the base of each mandibular appendage, sends out two outgrowths at
its end, of which an anterior branch or outgrowth will develop to the flexor mandibulae
and a posterior one to the salivary gland.
Formation of the corpora allata takes place in the wall of the apodeme of the flexor mandibulae. As a sign of beginning of their formation, proliferation of the cells
occurs near the middle part of the inner wall of each apodeme, but the proliferated
cells have essentially the same structure as cells of the apodeme wall in this stage.
With the lapse of time the proliferated cells become a cellular outgrowth or cellmass which is located in close contact with the inner wall of the crescent-shaped
apodeme in a cross section of embryo. This cell-mass is a rudiment of the corpora all ata. It is a solid elliptic body with no lumen (Fig. 1).
The origin and the process of development of the rudiments of corpora allata areof the same among four species studied belonging to a different genus respectively.
As development proceeds, the rudiments of corpora allata gradually grow in close
contact with the wall of mandibular apodemes (Fig. 2) and are carried dorsally by thegrowth of the latter. When the fusion of gnathal ganglia to form the suboesophageal
ganglion takes place, the corpora allata are carried more dorsally. Then they are cut off
as a pair of solid elliptic cell-masses from the wall of the apodemes and are deposited
between the inner wall of apodemes and the posterior arms of the tentorium (Fig. 3).
At this time the corpora allata of B. (A. ) alcinous alcinous, about 35 by 40 p. m in size,are composed of about 20 cells, that of L. japonica of about 8 cells and that of Par. glacialis of 4- 5 cells, in the sections.
As the brain moves at the revolution stage to the dorsal side of the suboesophageal

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M. Tanaka

ganglion, the corpora allata come to be situated under the ventral side of the brain between the mandibular apodemes and the posterior arms of the tentorium. Now the developing corpora allata are round or oval in shape, about 40 by 45 P. m in size in B.
(A. ) alcinous alcinous and about 35 by 35 p. m in Pap. machaon hippocrates.
At the embryonic moulting stage the corpora allata assume a shape of the roundbodies and then they take their definitive position at the posterior part of the extremities of the transverse bridge of the tentorium (Fig. 4). In this stage the corpora allata ofB.(A.)alcinous alcinous are about 40 p. m in diameter, consisting of about 35 nuclei in asection and those of Pap. machaon hippocrates about 30 p. m, consisting of about 25 nuclei
and those of Par. glacialis about 10 p. m, consisting of about 10 nuclei.
In the full grown embryos of the studied species the corpora allata are somewhat
smaller than those at the embryonic moulting stage, but they retain the same position
and form. This state of the corpora allata does not change until hatching.

Discussion
In the early stage of embryogenesis the manner of development of corpora allatain Par. glacialis, L. japonica, B.(A.) alcinous alcinous and Pap. machaon hippocrates is in its
fundamental points the same as the observed by Ito (1918, in Bombyx and Antheraea),Eastham (1930, in Pieris), Okada (1960, in Chilo) , Kobayashi (1983, in Neomicropteryx
and Nepticula) and Kobayashi and Ando (1983, in Neomicropteryx). That is, the rudiments of the corpora allata arise as a pair Qf ingrowths, or cell-masses, from the wall of
the mandibular apodemes, but there are some differences in their later stages of formation among the species. Okada (1960) has described in Chilo that the corpora allata
fused with the corpus cardiacum into a single body in the late embryonic stage, andIto (1918) has stated for Antheraea that they completely divided into two globular masses in close contact with each other. In the present four species, however, neither thefusion of corpora allata with the corpus cardiacum nor their division into two masses
were observed.

Acknowledgements
The author wishes to express his cordial thanks to Prof. Dr. Hiroshi Ando, Sugadaira Montane Research Center, University of Tsukuba, and Prof. Dr. Czeslaw Jura,Jagiellonian University for their kind advices and critical reading of the manuscript.

References
Eastham, L. E. S., 1930. The embryology of Pieris rapae. Organogeny. Phil. Trans. Roy. Soc. £ond.,
SeT. B 219: I-50.
Ito, H., 1918. On the glandular nature of the corpora allata of the Lepidoptera. Bull. Imp. Tokyo
Seric. Coll. I: 63-103.

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Kobayashi, Y., 1983. The Embryology of Primitive Moths, Neomicropteryx nipponensis Issiki andNepticula castanopsiella Kuroko (Insecta, Lepidoptera). Docrotal thesis, University of Tsukuba.
- - - - - , and H. Ando, 1983. Embryonic development of the alimentary canal andectodermal derivatives in the primitive moth, Neomicropteryx nipponensis Issiki (Lepidoptera,Micropterygidae}.J. Morplwl. 176: 289-314.
Okada, M., 1960. Embryonic development of the rice stem-borer, Chilo suppressalis. Sci. Rep. Tokyo
Kyoiku Daigaku, Sec. B 9: 243-296.

Author's address: Dr. M. TanakaKano High School, Nanyo-cho, Kano,Gifu 500, Japan