NORTH AMERICAN ACROLOPHIDAE — HASBROUCK 513 



In Acrolophus, fortunately, the genitalia of pinned specimens 

 usually extrude to an extent permitting identification to species. 

 Wlien the terminal vestiture of the abdomen is removed with a fine 

 brush, several genital structures usually may be observed. The uncus 

 is almost always visible and it may be seen in both dorsal and lateral 

 aspects. The gnathos, beneath the uncus, is often visible. Both of 

 these structures are useful in diagnosing species groups and occasion- 

 ally even species. The cucullus, representing the approximate apical 

 half of the harpe, is almost invariably extruded. This structure is 

 second only to the aedeagus in furnishing specific characters. The 

 uncus, gnathos, and cucullus are well sclerotized and usually appear 

 about the same in dried specimens as they do after having been cleared 

 in potassium hydroxide. The apical portion of the aedeagus is only 

 occasionally extruded in dried specimens, although it regularly appears 

 in such species as variabilis and macrophallus where the aedeagus is 

 greatly elongated. In most dried specimens, however, the aedeagus 

 is somewhat distorted through the shriveled condition of its mem- 

 branous vesica. Thus, it may be seen that many of the references to 

 the genitalia in the key may be utilized without the necessity of 

 clearing and dissecting the specimen beforehand. 



Key to the Species and Subspecies of Acrolophus 



(Based on males) 



1. Labial palpi greatly elongated, recurved back over head and extending across 



much of all of thorax; when denuded, with basal segment never the longest 



of the three segments 2 



Labial palpi (a) intermediate in length, recurved back over head but extend- 

 ing only shghtly onto anterior margin of thorax; or (b) short, only shghtly 

 to partly recurved back over head and not extending to anterior margin of 

 thorax; but in either case, when denuded, with basal segment always the 

 longest of the three segments 20 



2. Eyes naked 3 



Eyes setose 5 



3. Antennae strongly bipectinate 1. dorsimaculus (Dyar) 



Antennae simple, laminate (griseus) 4 



4. Cucullus of harpe with major portion broadly expanded, with only approxi- 



mate basal third considerably narrowed (fig. 30) . 



2a. griseus griseus (Walsingham), new combination 

 Cucullus of harpe with only approximate apical third broadly expanded, with 

 approximate basal two-thirds considerably narrowed (fig. 35). 



2b. griseus capitatus, new subspecies 



5. Each antennal segment completely encircled by ring of scales 6 



Each antennal segment clothed only dorsad or dorsolaterad with scales, or 



antennal segments complex and their processes free of scales 9 



6. Antennae unipectinate; uncus bifid (fig. 36) . . 3. texanellus (Chambers) 

 Antennal segments simple, globose; uncus with single process minutely and 



acutely bifid at extreme apex (figs. 41, 42, 48) ; {simnlatus-acornus-hicornutus 

 species group) 7 



