NO. 8 ANATOMICAL LIFE OF THE MOSQUITO SNODGRASS 3 



instar has been appropriately named by Hinton (1946, 1958a) the 

 pharate, or cloaked, stage of development. The pharate stage of the 

 pupa in the larval skin is commonly called the "prepupal stage of the 

 larva," but the larva has already ceased to be a larva, so the expres- 

 sion does not conform with the facts. The mosquito will demonstrate 

 a number of other errors commonly made by entomologists. 



The problem of explaining how an animal in its evolution has be- 

 come adapted structurally to its environment and a special way of 

 living is complicated in an insect such as the mosquito that lives two 

 entirely different lives. If adaptation affects two or more organs 

 separately, the matter is relatively simple, but when it involves 

 coadaptation in all parts of the animal, it is hard to understand how 

 evolution by means of natural selection has brought it about. On the 

 other hand, the technique of "special creation" is entirely incompre- 

 hensible. 



The writer began this work on a very meager acquaintance with the 

 anatomy of mosquitoes, especially of the larva and pupa. For its 

 completion he is deeply in debt to others, in particular to Dr. Alan 

 Stone and Dr. Richard H. Foote at the U. S. National Museum for 

 literature and the identification of species ; to Dr. Paul Woke of the 

 National Institutes of Health at Bethesda, Md., for an abundance of 

 live larvae; to Dr. Ernestine B. Thurman, also of the Institutes of 

 Health, and Dr. Jack Colvard Jones of the University of Maryland 

 for much supplementary information and a critical reading of the 

 manuscript ; to various authors for copied drawings ; and to Mrs. R. E. 

 Snodgrass for the typing. For morphological interpretations the 

 writer assumes entire responsibility. 



I. THE LARVA 



Mosquito larvae hardly need an introduction. They are the familiar 

 aquatic "wrigglers" or "wigglers" that everybody knows turn into 

 mosquitoes. Anatomically the most specialized parts of them are the 

 head, the feeding organs, and the respiratory system. A number of 

 good papers have been written on the larval anatomy, and the facts 

 of structure have been well-enough described, but the writers, par- 

 ticularly on the head and feeding organs, mostly disagree as to the 

 homologies of the parts, and consequently the different terminologies 

 used must be very confusing to students. Hence, in the following text, 

 the larval head and organs of feeding are given a disproportionate 

 amount of space in an effort to arrive at reasonable interpretations 

 and an acceptable terminology. Otherwise than in the head and feed- 



