INSECUTOR INSCITI^ MENSTRUUS 91 



The four main groups of Cidcx separate as follows : 



1. Harpes tufted, the basal process, when present, arm-Hke ; first uncal 



plate with an opening ligament 2 



Harpes comb-shaped, the basal process not arm-like ; first uncal 

 plate jointed in a socket or absent 3 



2. Side piece essentially unmodified Culex 



Side piece excavated, with false jointed arms Phalangomyia 



3. First uncal plate absent, the second produced and spatulate, 



Ddinocerites 

 First uncal plate present, forming an outer sht&th. . . .Melanoconion 



In more detail, with the characters shifted a little in order 

 to be more easily followed, the subgenera separate as below. 



In the following separation of species, it has been my aim 

 to recognize only such species as differ appreciably in the 

 genitalia and I have accordingly united all those with similar 

 genitalia unless they showed appreciable differences in adult 

 coloration or larval structure. In some instances I may have 

 united really distinct species, owing to the fact that differences 

 in larvae or habits were unknown to me. But even allowing 

 for this, there remains a very considerable change from the 

 account given in the monograph in the direction of the reduc- 

 tion in the number of species to be recognized. In the mono- 

 graph, we relied on the coloration of the adults and larval 

 differences, and we carried out this scheme consistently, at 

 the same time overdoing it a little. The study of the genitalia 

 has led me to make comparisons where we had not suspected 

 that comparisons should be made, and has resulted in the cor- 

 rection of certain errors of observation. When these cor- 

 rections have been made and a little more latitude is allowed 

 for variation in adult coloration, the account in the monograph 

 will not diff'er greatly from that here set forth. The errors 

 in that work all lie in the direction of too great subdivision of 

 species and are therefore most easily to be corrected. It is 

 perhaps unfortunate that a more intensive study of the male 

 genitalia of Culex could not have been undertaken before that 

 volume of the monograph went to press ; but multiplicity of 

 duties at the time rendered it impossible. 



