April, 1904 .] 
Galls and Insects Producing Them. 
123 
opened the egg can still be seen b'ing within the cavit}’. The 
embryonic development is as 3*et unfinished and three weeks 
elapse before the larva emerges from the egg to find around it the 
material prepared for its nutriment. In this case the w’ound 
caused bj’ the flj’ is the immediate exciting cause of cell activitj-, 
and leads to gall formation.” 
M. \V. Beyerinck, in a paper regarding the growth of the gall 
of Xematus caprea on Salix am3'gdalina holds a similar view. I 
have not seen this paper, but an abstract* of it sa3’s : ‘‘The 
production of the gall is undoubtedly due to the matter secreted 
b3’ the poison gland, which is, consequently, homologous wfith 
the poison of H3’menoptera aculeata ; when the insect does not 
deposit an egg in the wound which it makes, the quantit3' of 
albuminous matter poured into the vesicle is always less than 
when an egg is deposited ; by careful obseiwation it is possible to 
assure oneself that the size of the gall is alwa3’s proportional to 
the size of the wound and the quantit3' of albuminoid matter 
introduced. B3’ an experiment in which a deposited egg was 
punctured by a fine needle, it was shown that the gall is due to 
the parent and not to the egg ; but, of course, in such a case the 
gall remains small ; neither the egg nor the larva are necessar3" 
for its production, though their presence exercises a certain influ- 
ence on the regularit3' of their development.” 
The ovipositors of the Cynipidae var3’ in length and in the 
amount of coiling within the abdomen. All present the same 
general characters. So far I have been unable to detect aii3' 
relationship between the length and character of the ovipositors 
and the location and complexit3’ of the galls (Figs. 94 to 98). 
Adler claims that the egg is alwa3's deposited in or near the 
Cambium la3'er of the plant. I am inclined to accept this state- 
ment, but have made no special effort to verif3' it. If Adler’s 
observations are correct the length of the ovipositor would be 
associated not with the depth of the Cambium from the surface 
of that part of the mature plant affected, but with the location 
of the Cambium at the time of oviposition and with the difficul- 
ties which the insect would experience in forcing the ovdpositor 
to the desired point. 
Oviposition usuall3* occurs before the buds are open, and the 
eggs ma3' be placed in three positions ( i) in the stem, as in the 
case of Rhodites radicum O. S., R. globulus Bent., Andricus 
cornigerous O. S. ; (2) in the apex of the incipient stem as in 
Andricus clavula Bassett, and Holcaspis globulus Fitch ; or (3) 
in the leaves of the bud as in Rhodites bicolor Harris, Amphi- 
bolips confluentus Harris, A. inanis O. S., A. ilicifoliae Bassett, 
Xeuroterus irregularis O. S., A. seminator, Callirh3qis tumifica 
*^Jour. Roy. Micr. Soc., 1887, p. 746. 
