44 



American Midland Naturalist Monograph No. 3 



to four cylindrical or tapering, thin-walled papilliform processes known as the 

 anal gills. The number, length and shape of the gills are often used in classi- 

 fication. 



ANOPHELINE LARVAE 



Important characters used in classifying fourth instar Anopheline larvae 

 are shown in Figs. 19-22. The designation of hairs by numbers follows rather 

 closely that used by Christophers (40), with some modification. 



HEAD. (Fig. 19). — The antenna is an elongate, cylindrical organ, usually 

 somewhat spinose and possessing several structures of taxonomic value. The 

 antennal shaft bears the antennal hair (11) on its basal half, and several prom- 

 inent structures on its distal end; namely, a papilla, a finger-like process, a 



ventral 



^ 9|I 



Fig. 20. Thorax of Anopheles larva. A, Ventral and dorsal views of thorax (pro = 

 prothorax; meso. = mesothorax; meta. = metathorax) . Proihorax : (1-3), inner, middle 

 and outer submedian prothoracic hairs; (4-8), lateral hairs; (9-12), prothoracic pleural 

 hairs; (13), ventral submedian hair. Mesothorax : (9-12), mesothoracic pleural hairs. 

 Metathorax : (1), metathoracic palmate hair; (9-12), mefathoracic pleural hairs. B, C, 

 and D, Bases of pleural hairs of pro-, meso-, and metathorax rsepeclively. 



