REPORT ON MOSQUITOES. 13 



This phase of the investigation was intrusted to Mr. George 

 J. Keller, of Newark, a graduate in Pharmacy, who is also inter- 

 ested in some phases of Entomology. Mr. Keller attacked the 

 problem early in March and the results of his cellar studies in and 

 near Newark make interesting readings. ^\fter trying- a great 

 \-ariety of materials alone and in combination, Mr. Keller at 

 last settled upon powdered Datura sfraiuoiiiuiu and succeeded ir, 

 producing the desired effect. Datura straiiioiiiuiii is the common 

 "Jimpson weed," known as producing a narcotic poison, but 

 useful in asthmatic affections. The results of Mr. Keller's work 

 form part of this report. 



From April, 1903, to Ma3\ 1904, Mr. Clarence Van Duersen 

 was field and office assistant. He was largely responsible for 

 the care of the breeding- jars, of which there were sometimes 

 over twenty, each with a lix-ely wriggler population from which 

 adults were issuing almost daily. Mounting these after they 

 had been noted up was no small task, and the alcoholic material 

 preser\-ed in connection \\ith the breedings ran into hundreds of 

 vials, all of which it was necessary to label for future study. 

 In the field he was chiefly employed near New Brunswick and 

 succeeded not only in finding- the larvre of two species that had 

 never before been bred ; but in discovering two species that had 

 not even been described. From June to October 31, 1904, Mr. 

 Harold O. Marsh replaced Mr. Van Duersen, doing much the 

 same kind of work. 



During the seasons of 1902 and 1903, Mr. Otto Buchholz, of 

 Elizabeth, made a series of collections of mosquito specimens 

 found near his house, in the streets and indoors. The object of 

 the collections w^as to determine the species that were trouble- 

 some both indoors and out and whether, as the season advanced, 

 there was any change in the mosquito population. The collec- 

 tions were therefore made at five-day intervals throughout the 

 season, indoors and out, and a vei")- clear idea was obtained of 

 the character of the species flying. 



