PUPAL STAGES OF WEST AFRICAN CULICID.^. 11 



the head. At its back are muscular and glandular (?) structures, and passing 

 into it is the pharynx ; the part itself is formed of a number of minute 

 chitinous structures. T shall content myself with figuring this part as I have 

 found it in one species (PL IV, fig. 2), reserving for a future paper the 

 discussion as to its homologies ; yet I will say that I doubt the accuracy of 

 Meinert's determinations of the other parts, but as his nomenclature has been 

 adopted in all the best known works on the subject, I have no option but to- 

 follow it in the descriptions in this paper ; for to do otherwise, would only 

 hamper its utility and practical application. 



The Brushes. 



These are two chitinous processes studded with a multitude of sockets, in 

 which are inserted hairs v/hich vary, in the different species, in degrees of 

 thickness and complexity. They are moved by the four largest muscles in 

 the head, and are often the most prominent part of it (PL lY, figs. 8, 9, 19). 



In most cases the individual hairs are simple, but in two of the larvse 

 examined very remarkable developments were found. Those in Culex calif/i- 

 nosifSy Graham, are very beautiful microscopic objects, each hair having at its 

 end a minute comb. 



In Culex tujrijjes, var. fusca, Theo., the hairs are much fewer and stouter,, 

 and each hair is regularly pectinated for a great portion of its length (PL III 

 fig- 15). 



Nuttall and Shipley have beautifully described the manner in which the^ 

 brushes are used in Anoplieles macidipennis to sweep the water (/. c. p. 56): 

 ])ut the macidijjennis hairs are simple, and it seems probable that even the 

 most minute living organism would fail to elude these more modified and 

 complicated brushes. 



The Labrum. 



Looking down on the front of the head a plate is seen, often with two 

 curved short bristles at its sides ; this is the clypeus. In the middle, between 

 the brushes and below the clypeus, is a semi-circular plate with a rather 

 roughened edge. When this is dissected out, or a preparation is made- 

 permitting of its examination with high powers, it is found to cover an organ 

 of some complication (PL IV, fig. 7). The central portion consists of two 

 spines on an oblong base, which is behind a shorter piece of somewhat similar 

 form ; this is flanked on either side by a spine and a tuft of hair. It is a 

 little more than ^ mm. in breadth (PL IV, fig. 6). I find it in a Sinhalese 

 larva, and also in the African Cide.v dissimilis, Theo. 



The Mandibles. 



These are far more highly complicated than is usual in insects. The two 

 I have dissected out, namely, those of Cidex caliginosus, Graham, and 

 C. dissimilis, Theo., are easily homologised, part for part, with Nuttall and 



