244 PROCEEDINGS OF THE NATIONAL MUSEUM vol. in 



There are three general types of ejaciilatory apodemes shown in this 

 genus. All these apodemes have a median plate, one or two median 

 cells (basal and subbasal), and a pair of laterally extended wings 

 (pi. 6, figs. 32, 33). As a rule, those species with a large median plate 

 have large wings and those with smaller plates have smaller wings. 



Sabrosky (1948) found four distinct types of genitalia in the Nearctic 

 species of Ogcodes. These types were based primarily on the structure 

 of the ejaculatory apodeme. These and other types are discussed 

 below under the designated species groups of the subgenus Ogcodes. 



Wing structures: Although the wing venation of this genus is 

 relatively simple (pi. 3, figs. 6-13; pi. 4, figs. 14-21), and the veins at 

 times difficult to ascertain, Sabrosky (1944, 1948) found that the 

 presence or absence of vein Mj was quite significant in distinguishing 

 several named species that had been based mostly on color features. 

 Because of this character he was able to establish considerable syn- 

 onymy. He was able to show also the existence of a relationship 

 between the venation and male genitalia, and he used these features 

 as "species complex" characters. From my study of the genus it is 

 evident that m-cu and r-m crossveins are equally important, and by 

 using a combination of these and other veins it was found that not 

 only were species groups evident but also that the species themselves 

 for the most part could be identified by these features alone. 



In an attempt to examine the venation more closely, wings of 

 several species were mounted in balsam on slides, and it was found that 

 short, sparse, stout hairs covered most of the costa, being more dense 

 near the wing base, thinner near the tip, absent along the posterior 

 margin, but again present to some extent along the anal margin. A 

 few hairs were also observed on Sc, R4+5, and M4. Whether or not this 

 characteristic is of any specific value will have to be determined by 

 further study, but the presence of setae on the wing veins (as in several 

 other acrocerid genera) and on the wing membrane (such as in certain 

 species of Ocnaea Erichson and Villains Cole) may be useful in studying 

 evolutionary trends within the family. 



Other characters: It was found that the structure of the 

 antennae was quite variable within the genus, and antennae from 

 several species were mounted on slides for study. The antennae of the 

 species observed were found to be quite consistent for each species, 

 and the number of apical setae on the terminal segment, the presence 

 of a basal bristle on segment iii, and the great reduction of segment in 

 formed the basis for dividing Ogcodes into its three subgenera (pi. 5, 

 figs. 23, 25, 27). 



Another important specific character often overlooked is the type 

 and amount of body pile. The length and placement of pile seems 

 to be a fairly consistent group character in the subgenus Ogcodes. 



