626 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
contrast to the conditions seen in flies, phagocytes play a very unim- 
portant part in the metamorphosis. In this respect Lasius resembles 
the Lepidoptera, and the author agrees with Korotneff and Rengel in 
believing the peculiarity to be associated with the length of time occu- 
pied by the metamorphosis. When this is rapid, as in flies, phagocytic 
activity may be assumed ; when slow, the degenerative changes are 
self-induced, and phagocytes are unimportant. The two conditions are 
compared to the pathological states known as acute and chronic inflam- 
mation. The most important part played by phagocytes in Lasius is in 
connection with the cells of the fatty body, which are actually broken 
down by means of phagocytic cells. This the author considers to be 
due to the necessity for providing room in the abdomen for the rapidly 
growing organs, especially the gonads. The contrast between the phago- 
cytic and non-phagocytic types of development are well illustrated in 
a comparison of the development of the imaginal muscles in flies and 
in Lasius. While in the former the larval muscles are completely 
consumed by phagocytes ; in the latter, although the muscle is inter- 
penetrated by imaginal myoblasts, these do not exercise any apparent 
influence on the larval muscle fibres and cells. The latter undergo a 
gradual process of disintegration, due, according to the author, to ex- 
haustion of vitality produced by too active functioning. When disen- 
tegrated, the muscle fibres and cells form a liquefied mass, which is 
gradually taken up by the imaginal myoblasts. 
The paper includes detailed comparisons with the results obtained by 
other observers for different insects. 
Development of Mantis.* — Mr. T. D. A. Cockerell has made a few 
observations on the development of a species of Siagmomantis, and is 
unable to confirm what Pagenstecher described in regard to Mantis , e.g. 
as to the state of the legs, or as to a real ecdysis between the pupa-like 
form and the active young. The young insects did not hang by their 
threads to the ootheca “ for some days,” but ran about the morning after 
hatching. 
The Genus Trimerus.f — Dr. Alfred Nalepa gives an account of this 
genus founded by him for certain members of the family Eriophyidae, 
found either as parasites within galls or in diseased growths of woody 
trees. Fourteen species are known, three being now described for the 
first time. 
Wings of Insects.! — Messrs. J. H. Comstock and J. G. Needham 
continue their account of venation and tracheation, discussing in this 
instalment the Hymenoptera and Embiidae. It can be accepted as a 
firmly established fact that the courses of the wing-veins of primitive 
insects were determined by the courses of pre-existing tracheae. But 
there is little correlation in Trichoptera, Diptera, or Hymenoptera. 
Specialisation of Lepidopterous Wing.§ — Mr. A. Kadcliffe Grote 
finds that specialisation is manifested in two principal directions : — 
(1) the suppression of the media, common to both pairs of wings ; and 
(2) the suppression of the branches of the radius, confined to the fore- 
* Amer. Nat , xxxii. (1898) pp. 513-4 (2 figs.). 
t Zool. Jalirb. (Abth. Syst.), xi. (1898) pp. 405-11 (1 pi.). 
+ Amer. Natural., xxxii. (1898) pp. 413-24 (11 figs.). 
§ Proc. Amer. Phil. Soc., xxxvii. (1898) pp. 17-44 (3 pis.). 
