Carpenter et al.: Mosquitoes of Southern U. S. 39 



RESPIRATORY TRUMPETS. (Fig. 15B).— Each thoracic respiratory trumpet 

 consists of a closed tubular portion, the meatus, and an open portion, the 

 pinna. The ratio of the length of the meatus to that of the entire trumpet has 

 been much used in descriptions. The respiratory trumpets in the Anophelini 

 are short, truncated at the distal end, and have a rather large oblique opening 

 which terminates in a split. The respiratory trumpets in Culicines are variable, 

 but are usually elongate or broadly conical and unsplit. Other characters of the 

 cephalothorax are rarely used in classification. 



ABDOMEN. (Fig. 16). — The chaetotaxy of mosquito pupae has been studied 

 by various workers, including Baisas (4), Christophers (40), Macfie (107) 

 and Senevet (168). The bristles and hairs of the pupal abdomen are illus- 

 trated in the following general works: Christophers (40), Edwards (56) and 

 Evans (57). The presence of simple spines on the posterior comers of abdom- 

 inal segments III to VII and a fringed spine in the same position on segment 

 VIII is characteristic of the Anophelini. In the Culicini the corresponding 

 hairs are usually fine and branched and do not arise exactly at the posterior 

 lateral corners. These hairs are very long in the Megarhinini and are placed 

 well back from the corners of the segment. 



PADDLES. (Fig. 16). — The shape, position or absence of hairs, and length 

 and nature of the fringe of the paddles provide important diagnostic characters. 

 In the Anophelini, there are two hairs near the posterior end of the paddle, 

 the paddle hair arising near the hind margin, and the accessory paddle hair, on 

 the ventral side, arising a little in front of the origin of the paddle hair. In 

 the genus Culex there is a small accessory hair placed beside the small paddle 

 hair. In other genera of the Culicini, the paddle hair is either single or absent. 

 There is no paddle hair in the members of the tribe Megarhinini. 



Larval Characters 



The mosquito larva has three main body regions, head, thorax and abdo- 

 men, each of which possesses variable structures important in classification. 

 The general appearance of larvae and their main morphological features are 

 illustrated in Figs. 17 to 22. 



The head capsule is more or less globular in shape, somewhat flattened 

 dorso-ventrally, and formed of three large sclerites; a pair of latero-ventral 

 ocular sclerites (^epicranial plates) and a single dorsal plate, the clypeiis 

 (jronto-clypeiis) . A V-shaped epicranial suture is formed by the junction of 

 these three sclerites. The ocular sclerites bear the antennae anteriorly and the 

 imaginal and larval eyes mid-dorsally. The clypeus has attached to its median 

 anterior border the narrow preclypeus, which bears the preclypeal spines. Both 

 the ocular sclerites and the clypeus possess several pairs of important hairs. 



Although the mouth parts are ventral in position, parts of the labrinn 

 project anteriorly and are visible in a dorsal view. The labrum is composed of 

 a median piece, the hairy palatum, and lateral lobes bearing the mouth brushes. 

 The mouth brushes are little used in classification except for separating out the 

 predacious forms, such as Psorophora ciliata, P. howardii, and Megarhinus spp. 



