162 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 13, No. 8 
Out of these 86mm.’ were present in ventilation tracheae and could be expelled 
by a difference of 1 atmosphere, while the diffusion tracheae were very slightly 
affected by the same pressure. The normal renewal of the air in the venti- 
lation tracheae amounted to 55 mm.'*, and by deep respiration 68. Hence 
the ventilation of the tracheae built for that purpose was very complete, and 
as the speaker had pointed out, was necessary for an effective respiration. 
In conclusion Dr. Kroau pointed out the biological connection between 
the small size of insects and the tracheal form of respiration. By an increase 
in the size of the animal the difficulties of supplying the air through diffusion 
from tracheae increase considerably without an effective system of blood 
circulation. Hence the size of insects is limited by their peculiar respiratory 
system which is only adapted to animals of small size. 
The above lecture was well illustrated by lantern slides and summarizes 
the material included in the following four papers by Dr. Kroau: 
1. ‘‘On the composition of the air in the tracheal system of some insects.’’ Skand. 
Arch. Physiol., vol. 29, 1913. 
2. ‘‘Uber gas diffusion in den Tracheen.”’ Pfliiger’s archiv. fiir Physiologie, vol. 179 
1920, pp. 95-112. 
3. ‘Die Kombination von mechanischer Ventilation mit gasdiffusion nach Versuchen 
an Dytiscuslarven.’’ Pfliiger’s archiv. fiir Physiologie, vol. 179, 1920, pp. 113-120. 
4. ‘Injection preparation of the tracheal system of insects.’’ Videnskabelige 
Meddelelser Dansk naturhistorisk Forening, vol. 68, 1917. 
353D MEETING 
The 353d meeting of the Society was held December 7, 1922, at the New 
National Museum, with President GAHAN in the chair and 36 persons present. 
The following officers were elected for 1923: President, Dr. L. O. Howarp; 
First Vice-President, Dr. A. G. Bovina; Second Vice-President, R. A. CusH- 
MAN; Editor, Dr. A. C. Baxrr; Recording Secretary, Mr. C. T. GREENE; 
Corresponding Secretary-Treasurer, Mr. 8. A. Rohwer. Executive Com- 
mittee, A. N. Caupruu, Dr. A. L. Quarntance, Dr. J. M. Aupricu. Nomi- 
nated to represent the Society as Vice-President of the Washington Academy 
of Science, Mr. 8. A. Ronwer. 
Program: 
Dr. A. G. Bovine: The biology of the Blister-beetles. Much knowledge is 
still lacking of the life history and structural details of many of the Blister- 
beetles, this being especially true about our American ones. Out of 31 
North American genera we have complete biological records of only one, 
namely Epicauta described by Riley, and partial records of two, Hornia and 
Macrobasis; but the life histories are unknown of the remaining 29 genera, 
among which are forms as Megetra and Hupompha whose imagines show the 
most extraordinary features. 
The different stages of the metamorphosis of the Blister-beetles were given 
as the egg-stages, the six larval stages, the pupal and imaginal stages. The 
shape and size of the eggs, their number, the way in which they are deposited 
was explained in detail. 
The diet of the larvae was the next topic and a review was given of the 
results obtained by several authors who have studied this question; particular 
attention was paid to Dr. A. Cros’ papers. The first instars vary greatly 
in shape according to the nature of their food and especially according to the 
ways in which they reach their food supply. Thus the first instars of the 
Zonabrini, Epicautini and Lyttini feed either on young Mantes, gathered 
