OF WASHINGTON. 103 



HEIDELBERG, GERMANY, May 4, 1906. 



My Dear Sir: I had the pleasure to receive your paper, "The larvae 

 of Culicidae classified as independent organisms." When I first began 

 the study of N. Am. Diptera, in 1856, I never dreamed that within half 

 a century this study would reach a degree of progress and perfection 

 as your paper shows it to be the case ! 



Very sincerely yours, 



C. R. O. S. 



Mr. Knab then requested Doctor Stiles to state the ruling 

 adopted by the International Zoological Congress with refer 

 ence to species based upon larval characters. 



In reply Doctor Stiles said that there were two standpoints 

 from which to look at this question. The first was that of no 

 menclature and from this standpoint he thought the practice of 

 describing species from other than the adult forms was perfectly 

 allowable. Numerous species in different groups of the ani 

 mal kingdom have been described from some immature stage 

 and the descriptions and names under which -they were pub 

 lished have since been recognized as valid. From the stand 

 point of classification the question was, however, one of feasi 

 bility. In many cases the descriptions of immature stages are 

 of great value. As an instance, the descriptions of the eggs of 

 cestodes and nematodes are very important in clinical diag 

 noses, and clinical determinations are in these groups made on 

 the egg nine times out of ten. 



Mr. Morris said that it was customary among botanists, 

 especially among students of fungi, to recognize the earliest 

 name given to a plant regardless of what stage formed the basis 

 of the description ; and in publications these names were fol 

 lowed by Roman numerals to indicate which stage was de 

 scribed. 



Mr. Schwarz alluded to the recognition of descriptions of 

 the work of insects, as galls, etc. He asked Doctor Stiles 

 whether species based on the description of the structure and 

 form of the excrement should be considered valid. Doctor 

 Stiles replied that fossils described on the structure of the 

 excreta or of prints were accepted and he saw no reason why 

 the same rule should not apply to other animals. 



