-21- 



57. Apex of aedeagus gradually 

 curved from near base to 

 apex. 



- Apex of aedeagus bent into 

 a right angled process. 



58. 10th tergite with lateral 

 arms upcurved; a dorsal 

 projecting process on sur- 

 face of mesal lobe. Aedea- 

 gus sickle-shaped. fig- 90 



- 10th tergite lateral arms 

 straight with membranous 

 folds between; below 10th 

 tergite a pair of very 

 slender filaments. Aedea- 

 gus with membranous area 

 appressed to curved apical 



part. fig. 91 



59. Aedeagus with imbricated 

 portion below spiral pro- 

 cess, fig* 92 



-58 

 -59 



argosa Ross 1938 



Aedeagus without imbri- 

 cated portion below 

 spiral process 



fig. 93 



strepha Ross 1938 



angusta Ross 1938 

 pullatus Denning 1947 



Neotrichia Morton 1905 



The members of this genus are the smallest of the Hydroptili- 

 dae, they may be 2 mm. or less in length. They are easily recog- 

 nized by the presence of ocelli and a spur formula of 0-2-3. 



Species of this genus are more numerous in the tropical and 

 subtropical regions, however, 14 species are considered to occur in 

 America north of Mexico. They appear to be quite local in their 

 occurence, although they may be very numerous as shown by light 

 trap collections of N. halia Denning from Maine, 8,393 specimens 

 being taken from July 5 to August 8, 1959 from 4 towns in the 

 northern part of the state. The most widespread species is 

 N. okapa Ross recorded from 10 states and one province, being re- 

 corded from Maine to California and Quebec to Florida. Others as 

 N. halia occurs across northern U.S.A. from Maine to Wyoming and 

 N. vibrans Ross with an eastern U.S.A. distribution from Wisconsin 

 to Maine to Florida. 



Most species are distinct and readily separated, however, 

 those similar to N. okapa are more difficult to separate. Care in 

 preparing these insects must be exercised since they can be over- 

 cleared quite easily. 



