e:mergence 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 is found in the respiratory trumpets in the pups of certain species of Man- 

 sonia. These pupse 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 pupa? of mosquitoes will be found 

 in the number and arrangement of the setae 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 pupae of different 

 species. Generally speaking the pupae of the Sabethini have a more slender and 

 elongate abdomen. There is also much diversity in coloration. The Sabethini 

 have pale yellow pupse, in some cases marked with a dark pattern. The pup^ 

 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 dov.-n 

 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. 



