INSECUTOR INSCITI^ MENSTRUUS 87 



rods, topped by a single piece. This has been called the uncus, 

 which name we will retain. In the middle of the side piece 

 is a slight lobe, bearing about five stout spines crowded to- 

 gether, situated at the apex of a basal hollow in which the 

 uncus rests. In Uranotccnia the next step is seen. A second 

 basal organ is present, paired and opposed to the unci, which 

 have now lost the single terminal piece and appear as paired 

 organs. The new organs have been called the harpes ; but they 

 are not homologous with those of Culex and others ; Urano- 

 tccnia is clearly a side line. We mention the harpes here to 

 show the early stage of a second basal organ. Culiseta is more 

 directly in the line we are following. Here the unci form a 

 basal cylinder or cone, composed of paired parts, but wrapped 

 into a single organ by the revolute margins. True harpes are 

 present in Culiseta, but they are more or less modified. A 

 simpler condition is found in Megarhinus. Here the organs 

 are elliptical, concave, more heavily chitinized on one side, the 

 tip dentate. The side pieces have the basal area pouch-like, 

 hollowed to receive the basal organs, the tip of the pouch 

 forming a slight lobe with a group of three stout hairs. From 

 this point Orthopodomyia and Mansonia originated ; but they 

 do not lie in the direct line of Culex, one being a generalized 

 form parallel to Culiseta, the other an ofifshoot. Climacura 

 falls here, the genitalia having the unci undivided. It is inter- 

 esting, however, as the larva has become practically a true 

 Culex. In Cnlicella, the unci have begun to divide, the harpes 

 remaining as in Culiseta. The larvae of Culicella have not at- 

 tained the Culex ty-po^, but are still much as in Culiseta. The 

 next link in the chain is shown in Jamesia, an Old World 

 group in which the larvse are predacious and, therefore, spe- 

 cially modified. The harpes have assumed the Culex type, 

 with a crown of spines, and with this the genus Culex may 

 be said properly to begin. Lutsia goes a step farther, the sec- 

 ond plate of the unci being toothed, whereas it is perfectly 

 simple in Jamesia. The side pieces have a process at the apex 

 of the basal hollow, carrying three stout spines ; the harpes 

 have a crown of spines and a curved basal arm and the unci 

 are divided into two plates. 



