OTIPOSITION AND THE EGG OF LYCTUS BRUNNEUS. 225 
formation and maturation o£ the larvse of a polyembiyonic Encyrtid 
((Parasitic Hymenoptera), in which he refers to the existence of abortive 
embryos. He states : " It is remarkable to find that in the polyembryonic 
Hymenoptera a large region of the egg is entirely discarded. In fact, just 
that region of the egg which would have formed the head, brain, etc., of 
the embryo is rejected." 
It is the same area in the egg of L. hrunneus which becomes the larva's 
initial food. 
The similarity of the egg of L. brunneus to that of L. planicollis — as 
described and figured by Snyder (1916) — in their appearance up to the time 
of maturation, suggests that the embryological phenomenon of the former 
species must also exist in the latter. 
SUMMAET. 
1. The method and manner of oviposition in L. hrunneus is established and 
is found to be the same as in L. planicollis, which is that of depositing its eggs 
in the tracheae, vessels, or pores, and under the surface of the wood. 
2. The eggs incubate in 15 days. The young larva, which occupies barely 
half the length of the egg, does not hatch out at once, but proceeds to eat the 
residual yolk-mass contained in the anterior part of the egg. 
Acknowledgments. 
The investigation, of which this paper records part of the results, was 
suggested by Prof. H. jMaxwell Lefroy, Imperial College of Science, to 
whom the writer has to express his thanks, and to the Committee of the 
Scientific and Industrial Research Department, for a grant to carry on 
the work. 
The writer is also indebted to Dr. C. J. Gahan, Keeper of the Depart- 
ment of Entomology, Natural History Museum, for identifying specimens 
of L, hrunneus ; to Prof. Percy Grroom, Imperial College of Science, for 
identifying the various species of timber used in this work ; to Dr. L. T. 
Hogben, lately Lecturer in Zoology, Imperial College of Science, for his advice 
and assistance in regard to the egg of L. hrunneus ; to Dr. Hugh Scott, 
Cambridge Museum, for specimens of L. linearis ; to M. P. Lesne, Museum 
d'Histoire Naturelle, Paris, for sending two pieces of oak infested by 
L. linearis ; to Dr. J. W. Munro, Forest Entomologist, Board of Agriculture, 
and to Mr. W. Dallimore, Royal Botanic Grardens, Kew, for material. 
In addition, thanks are due to Dr. A. D. Imms, Rothamsted Experimental 
Station, for his advice and assistance in connection with the publication of 
this paper ; and to Prof. S. MacDougall for his efforts to get the original 
paper published as a whole. 
