EMERGENCE FROM PUPA 103 
size and length of the breathing trumpets between different species of mos- 
quitoes are numerous, but they furnish no characteristics which are diagnostic 
for genera or larger groups. The differences assumed to exist were based on 
the study of a very few species and with larger series they are bridged over by 
intergrading forms. Moreover, differences occur between species within a genus 
far more striking than any between genera. The best illustration of this is a 
species of Wyeomyia (W. circumcincta) which has exceedingly long and very 
slender respiratory trumpets; no characters appear on either the imago or the 
larva that are in any way abnormal for the genus. Another striking modifica- 
tion 1s found in the respiratory trumpets in the.pupe of certain species of Man- 
sonia. These pup do not come to the surface of the water, but remain sub- 
merged, attached to aquatic plants by their respiratory trumpets. Here the 
trumpets are armed at their apices with a stout chitinous spine by means of 
which the pupa pierces the stems or roots of aquatic plants to extract the neces- 
sary air from them. 
There is considerable difference in the shape of the paddles but the remarks 
just made regarding the respiratory trumpets will also apply here. It may be 
stated, however, that there is a striking difference between the two tribes 
Culicini and Sabethini. In the Culicini the paddles are large, broad and 
rounded in outline ; they are strengthened by a stout longitudinal mid rib which 
bears a spine or seta apically. In the Sabethini the paddles are much smaller, 
narrower and tapered to a point ; the mid rib is either absent or poorly developed 
and there is no terminal spine or seta. 
Perhaps the greatest diversity among the pupe of mosquitoes will be found 
in the number and arrangement of the sete on different parts of the body. 
These, we are sorry to say, have not been adequately studied, but we are con- 
vinced that they will furnish both generic and specific characters. Again there 
is a well-marked difference in the two tribes above mentioned. In the Sabethini 
the seventh and eighth abdominal segments each bear a pair of ample fan-shaped 
tufts at the apical angles; these are absent in the Culicini. 
There is, of course, some difference in proportions in the pupe of different 
species. Generally speaking the pupe of the Sabethini have a more slender and 
elongate abdomen. There is also much diversity in coloration. The Sabethini 
have pale yellow pups, in some cases marked with a dark pattern. The pupe 
of the Culicini are invariably darker, shades of brown and black being the usual 
colors. 
ECLOSION OF THE IMAGO. 
Towards the end of the pupal period the pupa becomes gradually inflated with 
air. It grows so light that it at last experiences great difficulty in going down 
into the water and when it succeeds it is carried to the surface again with great 
rapidity. Ecdysis takes place at the surface of the water and requires but a short 
time, although it is by no means as rapid a process as one would be led to suppose 
from the statements of certain authors. It is accomplished by the employment 
of air and Eysell has given a very excellent description of the process of which 
we give a translation herewith. 
