REPORT ON MOSQUITOES. 8i 



abroad in the evening and all night, indeed ; but which and how 

 many of them eat mosquitoes I do not know. 



Spiders destroy an enormous number of adults. I have fre- 

 quently lookexd over a series of webs in the morning and found 

 only mosquitoes in the toils ; sometimes one or two only, some- 

 times a great bunch of them reduced to little balls or dry husks. 

 It is probable that many spiders subsist largely on mosquitoes 

 and are among their most effective checks. 



Adult mosquitoes are sometimes infested with little parasitic 

 mites, bright red in color and usually attached to the underside 

 of the body behind the wings. This looks like and may be the 

 same species that is found on the common house-fly, but the two 

 have not been critically compared. Usually this mite is so rare 

 as to attract no attention ; but sometimes, as in the early summer 

 of 1904, it may become locally so abundant as to attract general 

 attention. The effect of this kind of attack is to weaken the' 

 insect and perhaps to shorten its life, while preventing reproduc- 

 tion. Unfortunately, we know little of the life history of these 

 minute parasites, or how they came to attach themselves to their 

 hosts. 



Againoniermis ciiUcis. 



A more effective enemy, unfortunately attacking only a single 

 species, so far as known, is the round worm described by Dr. 

 Charles Wardell Stiles as Agamoinennis culicis, in Bulletin No. 

 13 of the Hygienic Laboratory of the Marine Hospital Service. 

 The following is a copy of the description and of Dr. Stiles' 

 comments : 



"Group Agamomermis, Stiles, 1903. 



"Generic diagnosis. — Mermithidse : An artificial collective 

 group containing larval forms, which cannot be more definitely 

 determined because of lack of genital organs. As such a group 

 is artificial, it should have no type species." 



"Species Agamomermis Culicis, Stiles, 1903. 



"Specific diagnosis. — Agamomermis : About 1 1 mm. long ; 

 240 u. in diameter. Caudal spine, 88 u. long. 



"Habitat. — Abdominal cavity of Mosquitoes {Cidc.v sotlici- 

 tans). New Jersey. 



"Type specimen.— Collection U. S. P. H. & M. H. S., No. 



6 MO 



