28o REPORTS ON INVESTIGATIONS AND PROJECTS. 



Costa Rica, and made large collections, including two new to the 

 collection, both of which are new to science. 



Mr. A. Busck spent the summer in the West India Islands and 

 brought together a large collection, many of which he succeeded in 

 rearing from the larvae. From his results and those of voluntary- 

 observers during the summer, 20 species new to the collection were 

 brought together, of which 6 are new to science, 2 belonging to 

 genera not yet characterized. No less than 33 species were reared 

 from the larvae. 



The voluntary observer in Alaska has accomplished no results. 



In all there have been obtained in the course of the investigation 

 128 species of mosquitoes from North and Middle America (Central 

 America and the West Indies) ; but 8 of these belong to the short- 

 billed mosquitoes of the family Corethrinae, now placed in the 

 Dixidae. 



Much work has been done during the year in regard to illustration 

 and there are now finished drawings as follows : Drawings of adults 

 from North America, 68 species ; drawings of eggs, 31 species ; 

 drawings of pupae, 14 species ; complete drawings of larvae, 28, rep- 

 resenting 27 species ; drawings of details of larval structure, 367, 

 representing 56 species. The drawings of the adults are in pen 

 and ink ; those of the larvae and pupae are in wash ink, while the 

 eggs and details of the larvae are in charcoal. This enumeration 

 of drawings does not include field sketches. 



The important bearing of the work has already been shown in a 

 striking way by the fact that the Public Health and Marine Hos- 

 pital Service, during the yellow- fever epidemic of the past summer, 

 has based its quarantine regulations entirely on the results of the 

 studies of the geographic distribution of Stegoviyia fasciata made 

 during the summer of 1904 and referred to in the report of last year. 



Lillie, Ralph S., University of Nebraska, Lincoln, Nebraska. Grant 

 No. 166. Study of the relation of ions to the various forms of pro- 

 toplasmic movement. ^ r ,000. 



Abstract of Report. — Dr. Lillie continued the investigation of the 

 subject and reports on the following subdivisions : 



I. PhYSIOI^GGV of CEIvVDIVISION. 



The conditions determiriing the disposition of the chromatic filaments 

 and chroynosomes in mitosis. — The attempt was made to simulate the 

 arrangements exhibited by chromatic filaments and chromosomes 

 at the different stages of cell-division by the use of mutually repel- 

 lent models composed of groups of floating, similarly oriented, mag- 



