-24- 



11. Aedeagus with dissimilar 

 sclerotized hooks; tip 

 acuminate, membranous; 



spiral stout. fig. 104 riegeli Ross 1941 



- Aedeagus without hooks. -12 



12. Aedeagus: apex irregularily 

 expanded , membranous ; very 

 long, slender spiral pro- 

 cess. Claspers, lateral 

 view, curved ventrad, apex 



hook-shape, acuminate. fig. 105 elerobi Blickle 1961 



- Aedeagus: apex flattened 

 membranous, or flattened 

 elliptic with long apical 

 setae. A comb of setae or 

 an apical projection on 



8th sternite. -13 



13. Aedeagus: apex flattened, 

 elliptic, pair of apical 

 setae. 8th sternite with 



apico-mesal lobe. fig. 106 vibrans Ross 1938 



- Aedeagus: apex flattened, 

 truncate; no apical setae. 

 8th sternite with apico- 

 mesal comb of large setae, fig. 107 edalis Ross 1941 



Ochrotrichia Mosely 1934 



The genus occurs in the Nearctic and Neotropical regions from 

 Ontario and Maine west to the Pacific coastal states and south to 

 Peru, S.A. and in the West Indies. Although some species are found 

 in eastern U.S.A., the greater number occur in the western and 

 southwestern states. 



The adults are from 2 to 4 mm in length, from front of head to 

 wing tip. They have 3 ocelli and a spur formula of 0-'3-4. The 

 males usually have a simple tubular aedeagus, a spinose complicated 

 10th tergite and large claspers which are arranged on either side of 

 the 10th tergite. The shape and structure of the 10th tergite and 

 claspers are distinctive for each species and determinations are 

 based on these structures. 



Only a few species are known to have a wide distribution, 

 namely: 0. tarsalis from Ontario and Maine south to Florida and to 

 Central America; 0. stylata in the west from Washington and Montana 

 south to Central America; 0. spinosa from Minnesota and Wisconsin 

 south to Kentucky; 0. logana in Washington, Oregon, Idaho, Wyoming 

 and Utah with 0. lometa more southern in California, Utah, Colorado, 

 Arizona and New Mexico. It is quite possible that further study 

 will increase the known distribution of some species, an example is 

 0. wojcickyi known originally from Maine and New Hampshire but now 



