17 
In the summer of 1889 I collected a number of specimens of Agam- 
omerrnis sjp. from mosquitoes of the species Culex nemoralis taken in 
the vicinity of Leipzig, Saxon}\ Whether they were identical with 
the present form I am unable to state. The interesting fact may be 
mentioned, however, that the Leipzig Agamomermis was decidedly 
injurious to the mosquitoes. It was found in the abdominal cavity of 
larvae, pupae, and adults, so that infection must have taken place in the 
water, namely, in the larval and pupal stages of the Gulex. The 
infested insects were very sluggish in their movements and could 
usually be easil}" recognized as diseased. Many of them died from the 
effects of the parasite, and the ovaries of infected females were under- 
developed. Professor Leuckart informed me at that time that he had 
frequent!}^ found Culex nemoralis infected with this worm, and that 
during the years that the worms were most common the mosquitoes 
seemed to be less numerous. 
These cases represent interesting instances in nature, where a pest 
is subject to other pests which tend to hold the former in check. 
At least two other species of Afermis should be placed in the collec- 
tive group Agamomermis^ namely, Agamomermis gammari (von Lin- 
stow, 1892), parasitic in Gammarus jmlex, and A. sialidis {von Linstow, 
1892), parasitic in Sialis lutaria. 
Bibliography . — Bibliographic citations follow the references in 
Stiles & Hassall, Index-Catalogue of Medical and Veterinary Zoology, 
Bull. 39, Bureau Animal Industry, U. S. Dept. Agile., Wash. 
24316— No. 13—03 2 
