Chi 38 



Chiasma. — The ceniral body of nervous matter 

 formed by the junction and decussation of the 

 optic nerves. (Gr. chiasma, the mark of a )^ 

 {chi) or cross.) 



Chitin. — The hard shell-like outer skin of arthropods 

 and hard cased insects. The chemical formula 

 of Chitin is CigHooNoOj^. (Gr. chiton, a tunic.) 



Chitinous. — Pertaining to the chitin. (Gr. chiton.) 



Chordotonal Organs. — Compact, spindle-shaped 

 groups of sensillse, each consisting of a chit in- 

 secreting gland and a nerve cell, hung between 

 two points of the cuticle, or between the cuticle 

 and some internal organ. These sensillse are 

 connected with nerve fibres and believed to 

 receive and transmit sound vibrations. (From 

 Gr. chorde, an intestine, a cord ; L. chorda, a 

 cord.) 



Chorion. — The shell of the egg ; the firm chitinous 

 outer layer of the egg (see Ovaries). (Gr.) 



Chromatin. — The thread-like material which 

 appears netted and looped, situated in the 

 nucleus. See Achromatin. (From Gr. chroma, 

 colour.) 



Chrysalis. The quiescent state the larva assumes 

 when full fed. Generally applied to Lepidoptera. 

 (Gr. chnjsos, gold.) 



" ChyUfic Stomach." — The mid-intestine. (Gr. 

 chyles, juice, from chco, to flow ; and stomachos.) 



Cibarial apparatus.— The organs which operate 

 upon the food brought to the mouth. (L. 

 cihus, food ; and ad, and faro, to prepare.) 



