ON THE LARVAL AND PUPAL STAGES OF WEST AFRICAN 



CULICID^. 



By ay. AVESCHE, E.E.M.S. 



"With Eield-Notes by the Collector, Dr. W. M. Geaham. 



(Plates I.-VII.) 



In dealing with this extremely interesting and valuable collection o£ Mosquito 

 larv8e and pupse from Lagos, which we owe to the industry o£ that in- 

 defatigable collector and observer. Dr. W. M. Graham, I have endeavoured to 

 give a practical and not too technical description of each species, and I have 

 given illustrations of all the principal characters, and of some points of more 

 general interest. If technicalities are indulged in, they are explained in the 

 preliminary text, and in the plates. It has been my object to make it 

 impossible for the careful worker to mistake any one of these larvse for that 

 of another species, but persons who have experience of such work, know the 

 difficulty of arriving at such results without a knowledge of all known forms, 

 and that knowdedge I have no pretensions to possess. 



In my keys I have taken the most simple and obvious characters as 

 guides, and I may point out for the information of those who approach the 

 subject as novices, that with a little experience it ought to be easy to 

 recognise the two most dangerous groups of mosquitoes in their larval stages : 

 the Anophelines by the absence of the respiratory tube or siphon, and the 

 presence of long feathered plumes on the thorax ; and the Stegomyice by the 

 short stumpy siphon, often with serrated spines, and the numerous star-like, 

 or stellate, hairs scattered all over the body (PL III, figs. 3 & 7) ; while larger 

 heads and longer stout siphons suggest, if the spines are serrated (PI. II, 

 fig. 10), a relationship to the genus ^des ; and the very long thin siphons 

 have been recognised as sometimes belonging to the restricted genus Cidex. 

 The paper is arranged in the following order : — 



1. Technique, including measurements and the examination of living 



larvae. 



2. Characters of the larv?e and pupse. 



3. Keys to the species described, larva? and pupa\ 



4. Separate description of each species. 



5. Plates and explanation. 



BULL. EXT. PvES. VOL. I. PART I. APRIL I9IO. 



