730 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
curvature of the germinal streak, this species of Meloe comes between 
Lina and certain Hymenoptera. Of the gastroptyche only the caudal 
part at first developes ; this extends forwards in two lateral processes, so 
that the contour has the form of the letter M ; between the two lateral 
lobes the ptychoblast appears ; the primitive head-lobes are still 
uncovered, even when the caudal fold has almost reached them ; the 
ectoptygma persists as in Lina. The upper lip arises from paired 
swellings on the anterior margin of the protocephalon. The rudiments 
of the antennae are visible even when the blastopore is still recognizable. 
The appendages of the first abdominal segment appear almost at the same 
time as the buds of the thoracic appendages, with which they are evidently 
homologous. On the following abdominal segments the appendages, 
whose existence is denied by Carriere but observed by J. Nusbaum, are 
at a certain stage distinctly bilobed. There are eight, not seven pairs 
of abdominal stigmata. Three pairs of Malpighian vessels arise as 
evaginatious of the proctodaeum. The incipient brain exhibits a single 
patch of dotted substance, most of the ventral ganglia show two. On very 
young embryos of Hydrophilus piceus , Graber has observed the bilobed 
character of the most anterior abdominal appendages. In very young 
embryos of Gryllotalpa vulgaris , the earliest rudiments of the most 
anterior abdominal appendages show the characteristic trilobed form of 
the thoracic appendages. Finally, Graber dissents from Cholodkovsky’s 
interpretation of “ lateral gastrulation.” 
Abdominal Appendages of Insect Embryos.* — Dr. v. Graber once 
more returns to the problem of the morphological import of the 
ventral abdominal appendages of insect embryos. Wheeler and Carriere 
regard these structures, especially the most anterior, as glands which 
were functional in ancestral forms. Graber regards them as remnants 
of appendages. The development suggests this ; so do those cases in 
which they persist throughout life ; the incipient rudiments are some- 
times segmented ; they may contain, like the limbs, a mesocoelic diverti- 
culum ; such are some of the arguments which Graber uses. He gives 
a table showing the different ways in which the appendages are reduced. 
The anterior or “ prosthypogastric ” structures may be reduced by 
constriction, by invagination, or by both, or by gradual flattening off ; 
in the latter way most of the posterior or opisthohypogastric appendages 
disappear. 
Protective Mimicry in Insects.f — Mr. E. B. Poulton draws attention 
to a Homopterous Insect from British Guiana, which mimics a leaf- 
carrying ant carrying its leaf. He suggests that we have, here to do 
with a palatable insect much relished by insect-eating foes, which 
defended itself by acquiring a protective resemblance to leaves. The 
green colour and compressed body were probably evolved in response to 
the need for concealment. As the foes increased in acuteness, and pene- 
trated this common disguise, it became of advantage to certain hard- 
pressed forms to resemble something which was positively objectionable 
to their enemies rather than merely useless and uninteresting. In the 
present case the transition from protective resemblance to protective 
* Morphol. Jahrb., xvii. (1891) pp. 467-82 (6 figs.). 
t Proc. Zool. Soc. Loud., 1891, pp. 462-4 (1 pi.). 
