THE MOSQUITOES OF THE SOUTHEASTERN STATES 9 



In the North the females of Gulex, Anopheles, and some other 

 mosquitoes hibernate. True hibernation of Anopheles apparently 

 does not occur in the South, as the females become active during warm 

 periods and larvae are found in the breeding places (i, 7, 22, 50, 119). 

 The same is true of some of the culicines in the warmer sections 

 (37, 57). Aedes and Psorophora pass the winter in the egg stage, 

 although some winter development of A. sollicitans occurs along the 

 south Atlantic and Gulf coasts (52). 



The piercing organs of the female mosquito consist of six elongated 

 parts enclosed in a flexible sheath called the labium. When the 

 mouth parts are inserted in the skin for bloodsucking, the sheath is 

 bent backward in the middle like a bow. There are two pairs of 

 slender cutting organs, the mandibles and the maxillae, and two addi- 

 tional organs called the hypopharynx and the labrum-epipharynx. 

 The latter is channeled, and the last two organs, when pressed 

 together, form a tube through which blood and other liquids are 

 drawn. A very small separate duct is found in a ventral thickening 

 of the hypopharynx, through which is injected the secretion from the 

 salivary glands. This salivary secretion is responsible for the itching 

 sensation caused by mosquito bites. Not all species of mosquitoes 

 have bloodsucking females. In the genus Megarhinus the proboscis 

 of the female is not adapted for piercing, and some of the species in 

 other genera are not known to take blood meals. 



The mouth parts of the male are not adapted for piercing, and the 

 males probably subsist on the nectar of flowers and fruit juices. 

 Both the males and the females can be kept alive in the laboratory 

 for considerable periods on fruit juices or sirups. 



COLLECTION AND PRESERVATION OF MATERIAL 



Anopheles larvae are usually found at the surface of the water 

 among aquatic vegetation or floating debris and are collected by 

 skimming through such material with a dipper or pan. A white- 

 enameled dipper, having the handle lengthened by the insertion of 

 a cane or smooth stick, makes a convenient implement for collecting 

 larvae. Around emergent vegetation or logs the larvae may be 

 drawn into the dipper by submerging one edge so that the water 

 flows in rapidly as the dipper nears the obstruction. The larvae 

 may be removed from the dipper to the collecting jar with a large- 

 mouthed pipette provided with a rubber nipple (fig. 5), or a spoon 

 may be used for this purpose. Wide-mouthed bottles (2 to 6 ounces) 

 make convenient collecting jars. 



Uranotaenia larvae and certain species of Gulex, especially G. 

 erraticus, are taken frequently with anophelines. Many other mos- 

 quito larvae, however, particularly those of Aedes and Psorophora, 

 are more active and usually drop to the bottom of the pool as soon 

 as disturbed. A quick plunge of the dipper is required to inter- 

 cept these larvae, or they may be collected by sweeping through the 

 water with a cloth collecting net or a fine-meshed wire strainer. 

 Other kinds of mosquitoes, such as Mansonia, Wyeomyia, the tree- 

 hole breeders, etc., require a special technique depending upon the. 

 character of the breeding place. 



