NO. 8 ANATOMICAL LIFE OF THE MOSQUITO — SNODGRASS 1 5 



species of Theobaldia [Culiseta], Lutzia, and Armigeres by Cook 

 (1944a). 



In the predaceous larvae of Toxorhynchites the brushes are sup- 

 ported on prominently projecting lateral lobes of the labrum (figs. 

 1 D, 4E). The brushes are narrow, stiff, and falciform, and appear 

 to be grasping organs, but as observed by Breland (1949) and by 

 Horsfall (1955) they are not used for obtaining prey. Just mesad of 

 the base of each brush is a small, slender sclerite (fig. 4 E, Tor). 

 Dissection reveals that this sclerite has a connection with the base 

 of the brush (F) and gives attachment to two large muscles, leaving 

 no doubt that it is the torma. 



The preoral cavity. — The undersurface of the labrum is continuous 

 with the so-called epipharyngeal surface below the clypeal region, 

 which extends back to the mouth. In most adult insects the part of 

 the preoral cavity above the base of the hypopharynx becomes a special 

 food pocket, the cibarium, opening directly into the mouth. In the 

 mosquito larva the shortness of both the labium and the hypopharynx 

 leaves the entire preoral cavity open below, but still it serves as a 

 channel for water carrying food particles to the mouth. In the tipulid 

 larva, however, there is a short cibarial pocket (fig. 7 A, Cb) above 

 the hypopharyngiolabial lobe just in front of the mouth. In the adult 

 mosquito and other sucking insects the closed cibarium becomes a 

 preoral sucking pump. In the mosquito larva the pharynx assumes 

 the sucking function. 



The epipharyngeal apparatus. — Lying in the epipharyngeal surface 

 between the posterior ends of the tormae is a structure that serves to 

 comb food particles from brushes on the mandibles. Since it is 

 musculated, and hence functions actively instead of passively, this in- 

 strument has been termed by Schremmer (1949) the Epipharynx- 

 apparat. Other writers have called it the "palatal bar," the "epi- 

 pharynx," and the "epipharyngeal armature." It includes a transverse 

 bar and groups of setae or other structures arising in front of the 

 bar. The crossbar is usually bow-shaped or V-shaped with the arms 

 diverging forward to the posterior ends of the labral tormae. The 

 setal accompaniment of the bar is quite different in different species. 



In Aedes (fig. 8 A) the epipharyngeal apparatus is relatively simple. 

 The bar is slender, gently curved forward, and its ends appear to be 

 connected with the tormal apodemes. Arising in front of the bar 

 are two large brushes of stiff hairs that converge posteriorly beneath 

 the bar. At the sides of the brushes arise a pair of large, tapering, 

 hair-bearing processes directed posteriorly, and at the base of each are 



