734 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
The nervous system may be seen in its earliest stage while the 
blastopore is still open; large ectodermal nerve-formative cells sink 
beneath the surface and become arrayed in four long rows on each side 
of the blastopore. When this last closes another, median, row is formed. 
The cell now appears to bud off daughter-cells which become ganglionic. 
The brain is directly continuous with the ventral cords. The optic nerve 
fibres seem to grow out from the brain towards the ommatidium. 
The mesoderm is early split up into eighteen pairs of blocks which 
become hollow ; in the walls of some of the sacs so formed central cells 
become germ-cells ; falling into the cavities they multiply by karyo- 
kinesis. Solid diverticula from six successive masses form the latter into 
a continuous gonad. The generative ducts also arise from the meso- 
dermal sacs. In the marked metameric characters of the gonads and in 
the formation of the ducts as coelomic diverticula Mr. Wheeler sees 
resemblances to Annelids, as, indeed, he does also in the mode of forma- 
tion of the central nervous system. 
Life-Histories of Ceratocampidae, &c.* — Prof. A. S. Packard finds 
that the most generalized forms of the Ceratocampid Moths are Dryo- 
campa and Anisota. An account is given of the life-history of D. rubi- 
cunda and of three species of Anisota ; Sphingicampa bicolor is the most 
Sphinx-like of any Ceratocampid or other Bombycid known to the author 
in the shape of the head and its markings, the four thoracic horns, the 
caudal, the heavy anal legs, and the skin granulated with white tubercles. 
Full accounts are given of Eacles imperialis and Citheronia regalis ; and 
here, as in other cases, a distinction is made between the “ congenital 
characters ” and the “ later adaptational characters.” After some notes 
on various Hemileucidee, the author passes to the Lasiocampidae. In them 
there may sometimes be noted an acceleration of the development of 
setae, which, in their ancestors, were characters acquired during the 
later stages of the larval life. From the various larvae of this family, 
of which complete or partial accounts are given, no points of general 
interest are drawn. 
Colours of Lepidopterous Larvse.f — Prof. E. B. Poulton has an 
abstract of a memoir entitled “ The experimental proof that the colours 
of certain Lepidopterous Larvae are largely due to modified plant-pig- 
ments, derived from food.” He divided into three lots one batch of eggs 
laid by Tryphsena pronuba, and fed them (in darkness) on green leaves, 
yellow etiolated leaves, and white mid-ribs of cabbage. The last, whose 
food contained neither chlorophyll nor etiolin, were entirely unable to 
form the green or brown ground-colour. 
Lepidopterous Pupa with Functional Mandibles.J — Hr. T. A. 
Chapman remarks that it seems at first sight incredible that a lepi- 
dopterous pupa should not only have jaws, but have them of immense 
size proportionately to the insect, and functionally active. After 
describing these organs he points out that there are no muscles attached 
to the jaws, and no imaginal jaws within them, whose movements compel 
those of the pupal jaws. The characters of the pupa, especially as 
* Proc. Amer. Phil. Soc., xxxi. (1893) pp. 139-92 (7 pis.), 
t Proc. Roy. Soo. Lond., liv. (1893) pp. 41 and 2. 
j Trans. Entoraol. Soc. Lond., 1893, pp. 255-65. 
