PREL工M工NARY NOTES ON THE EMBRYONIC DEVELOPMENT OF THE PRIMIT工VE
MOTH，]!:RIOCRAN 工~ SP. ON ALNUS (LEPIDOPTERA: ER工OCRANI工DAE)

Yukimasa Kobayashi and *Hiroshi Ando
Department of Bio1ogy，Saitama Medica1 Schoo1，
981 Kawakado， Moroyama，Saitama，
350‑04 Japan女

Sugadaira Montane Research Center，Univ巴rsity of Tsukuba，Sanada，Nagano，386‑22 Japan

We have investigated the embryonic deve10pment of severa1 primitive
Lepidoptera， such as ~eomicropteryx nipponensi~

in the suborder Zeug10pt巴 ra!
:. 三よ旦全旦豆主主 in the(Kobayashi & Ando，1981，1982)，Endoclita excrescene and ].
，suborder Exoporia (Ando & Tanaka，1976，1980; Kobayashi et al1981)，andrevea1ed that the mode of their embryonic deve10pment is 1arge1y different
from that of the advanced suborder D工trysia in some important respects，but issimi1ar to that of the c1ose1y re1ated order Trichoptera. However，nothing
was known about the embryogenesis of other primitive Lepidoptera，such as them巴 mb巴 r of the suborder Dacnonypha.

In the present study we describe theexterna1 f巴 atures of the deve10ping embryo of one of the eriocranid species
be10nging to the Dacnonypha，and discuss th巴 ir phy10genetic significanc巴 s fromthe comparative embryo1ogica1 standpoint.
The eggs of Eriocranii
3c sp. on 主よ旦旦~ are 1aid in the tissue of leaf budsof !
lよ旦旦.e i.旦2主込旦主~・The new1y 1aid egg is 巴 10ngated ovoid，about 0.48 by 0.23

mm in size and 1ater it progr巴 ssive1y 工ncreases to about 0.62 by 0.35 mm.

Theoegg period is about 6 days at the temperature of about 20 C.
The features of embryon工c deve10pment 工n this sp巴 C 工巴 s are as follows:

1. The germ disk is very large as in the case of th巴 ditrys工an specles，
whereas the germ disk of the Zeuglopt巴 ra and Exopor工a is sma11.
2. The germ disk differentiates into a 1arge germ band i.旦立主主Q・ The

invagination of the germ disk into the yo1k as observed in the Zeugloptera and17

18
Exoporia does not form.
3. Embryonic membranes are formed by the fusion of amnio‑serosal folds.
工n the mode of embryonic membrane formation，this situation is assumed to be

an arch巴 type of the fau1t type in the advanced ditrysian embryo.
4. The germ band develops on the yo1k surface as in the case of thezeuglopteran and trichopteran eggs. On the other hand，the germ band of theexoporian and ditrysian Lepidoptera sinks into the yolk.
5. In spite of the superficial germ band typ巴

embryonic m巴mbranes per‑sist even after dorsa1 closure of the embryo; therefore，the secondary dorsalorgan does not form.

This situation is common to all other Lepidoptera 巴xcept

for the Zeugloptera in which the organ forms.
6. 工n the early germ band，two temporary transverse furrows form，one in
the posterior gnatha1 segments，the other in the anterior abdominal segments.
The former is somewhat similar to the cephalic furrow in the dipteran embryos.
However，furrows of this kind have not been observed in any other 1巴pidopteranembryos; thus，the formation of these furrows seems to be characteristic of
the Dacnonypha.
7. In the egg of the pr巴 ‑revolution stage，hydropyle cells are present on
the dorsal surface of the egg・ This feature is common only between theZeug10ptera and Dacnonypha.
To summarize，against our initial assumption，it became evident that theembryonic development of the eriocranid species，as a whole，has closer
affinity to that of the advanced ditrysian Lepidopt巴工 a than to that of otherprimitive Lepidoptera，such as the Z巴ugloptera and Exoporia.

References
Ando，H. and M. Tanaka (1976) Proc. Jpn. Soc. System. Zoo1.
， 12:52‑55.
ーーーーーーーーーーー.

(1980) Int. J. Insect Morpho1.Embryo.，9:67‑77.

Kobayashi， Y. and H. Ando (1981) J. Morphol.
， 169:49‑59.
ーーーーーーーーーー.

(1982) J. Morphol.，172:259‑269.

Kobayashi，Y.，M. Tanaka，H. Ando and K. M工yakawa (1981) Kontyu，49:641‑652.

Proc.Arthropod.Embryol.Soc.Jpn.，
1<J85