26 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
impressions ; tlie latter do not act when the insect is flying. There is not 
yet any evidence that the light-perceptions are sufficiently complex to bo 
entitled to be called seeing, but, as the large development of the com- 
pound eye permits the simultaneous percejjtion of movement, its direc- 
tion, and of lights and shades over a given area, a dragon-fly may 
pursue and capture another insect without seeing it in our sense of the 
word seeing. Dr. Sharp suggests that a set of observations should 
be made to test to what extent covering the optic organs with pigment 
is effectual in excluding light from them. It is, further, necessary to 
observe and delineate the actual tracks made by particular species when 
escaping from Plateau’s labyrinth, the tracks as yet given being only 
diagrammatic. 
a. Insecta. 
Distasteful Insects.* * * § — Mr. E. B. Poulton has a somewhat sharp 
reply to Mr. Butler’s observations,']' and his only object is to enlighten 
“ readers who may mistake the expression of Mr. Butler’s conviction 
that his notes occupy an altogether unique position for a compre- 
hensive guide to the literature of the subject.” To this Mr. A. G. Butler 
replies J by quoting the observations he communicated to Mr. Poulton 
some time since. He considers it noteworthy that no insect in any 
stage excepting the red-tailed humble-bee (which was only offered to 
the Missel-Thrush) was rejected by all his birds ; those insects which 
were refused by certain species were eagerly devoured by others, so that 
it was impossible to conclude that any of them enjoyed perfect immunity 
from destruction. His birds did not learn by experience to reject 
with scorn that which they had proved to be unpalatable, and in some 
instances they seemed to acquire a taste for larvae previously refused. 
“ Birds are very intelligent, but their memories are ridiculously short.” 
As to Mr. Boulton’s remark that birds are afraid of large sjhders, Mr, 
Butler points out that the larva of Staurojpus fagi docs not leave the 
egg full-grown. 
Abdominal Appendages of Insects.§ — Dr. E. Haase has investigated 
the abdominal appendages of Insects, and especially of the Thysanura, 
with especial reference to the affinities of the Myriopodn. He finds it 
necessary to distinguish between the soft ventral saccules, which can 
be evaginated, and which are generally known as segmental or crural 
glands, and the stump-like appendages which he calls “ Bauchgriflfel.” 
The ventral saccules of Scolopendrella are developed from the third 
to the eleventh segment of the trunk ; it is pointed out that they may 
bo filled with blood, and are drawn in by a special muscle ; their cuticle 
is smooth, has no distinct pores, and the nuclei of their matrix are very 
large. Among the Diplopoda we find saccules of similar structure, but 
with a simpler matrix and better developed retractors ; they lie in the 
third pair of legs of both sexes of Lysiopetalum, Polygonium, and Sipho- 
nopliora. In the Chordeumidm a few are found between the copulatory 
feet of the male, where they serve as receptacula seminis. In Campodea, 
* Ann, and Mag. Nat Hist., iv. (1889) pp. 358-GO. 
t See this Journal, 1889, p. 633. 
j Ann. and Mag. Nat. Hist., iv. (1889) pp. 463-73. 
§ Morphol. Jahrb., xv. (1889) pp, 331-435 (2 pis ). 
