Mr. J.8. Baly on new Genera and Species of Phytophaga. 483 
between the dark and light portions. Such a line of demarca- 
tion makes its appearance when the body has grown to about 
0-3 millim. in length ; the paler and darker portions then appear 
very like a small acorn in its cup. Subsequently the pale por- 
_tion becomes elongated, and grows into the caudal part of our 
structure ; whilst the darker head portion gradually acquires a 
conical form, and the foremost membranous part commences its 
motory activity; but the tail, contrary to what occurs at a later 
period, is still distinguished from the head by its much lighter 
appearance, and, instead of seminal filaments, its surface is co- 
vered with small, roundish, transparent granules (vesicles ?), 
thus reminding one of the globular or clongated bodies on which 
the seminal filaments are developed, for example, in the body- 
cavity of the Annelida. 
XLIX.—Deseriptions of new Genera and Species of Phytophaga. 
By J. S. Baty. 
Fam. Sagride. 
Sagra mutabilis. 
S. supra subopaca, subtus nitida; antennis extrorsum nigro-purpu- 
reis; thorace subquadrato, antice vix producto, angulis anticis 
modice prominulis; elytris basi thorace multo latioribus, humeris 
subprominulis, a basi ad apicem angustatis, supra convexis, intra 
humeros sat profunde impressis, subtiliter coriaceis, infra basin 
minus profunde transversim impressis, tenuissime gemellato-punc- 
tato-striatis, striis fere omnino deletis. 
A. Corpus rufo-igneum. C. Corpus viridi-ceeruleum. 
B. Corpus viridi-aureum. DD. Corpus purpureum. 
Mas. Femoribus posticis sat elongato-incrassatis, elytra sat 
superantibus, subtus bidentatis, dente antico majore; tibiis ejus- 
dem paris apice mucronatis bidentatisque, dente exteriore valido, 
abdominis segmento primo deplanato, crebre punctato, tomentoso. 
Fem. Elytris oblongis, postice minus angustatis; femoribus 
posticis elytra vix superantibus, subtus ante apicem crista brevi 
instructis ; tibiis ejusdem paris apice breviter mucronatis. 
Long. 8-11 lin. 
Hab. Cambodia, Siam. 
This lovely species is most closely allied to S. speciosa, Lac. : 
it agrees so completely in nearly all its characters with that in- 
sect that a detailed description would be almost useless. I shall 
therefore confine myself to the points of difference between the 
two insects. 
In 8S. mutadbilis the antenne are equally long, but stouter ; 
the thorax is usually (but not always) slightly broader; the 
elytra are much broader at their base, the humeral callus being 
Ann. & Mag, N. Hist, Ser. 3. Vol. xiv. 28 
