T. D. A. COCKERELL. 95 



Fourth abdominal segment covered with black tomentum lycii Ckll. 



Fourth abdominal segment with a very broad light band, the black confined to 

 the base 1. 



1. Apical fringe of fifth abd. s. black, except at extreme sides. 



cordleyi Viereck. 

 (Cordlei/i goes south to ('aliforuia, as shown by a specimen in the Cresson col- 

 lection.) 

 Apical fringe of fifth abd. s. pale or ferruginous 2. 



2. Hind spur of hind tibia hooked at end dilecta (Cress.). 



Hind spur of hind tibia not hooked 3. 



3. Larger, length of anterior wing 12 mm. ; bands of abdominal segments 2 to 4 



greyish white Speciosa (Cress.). 



Smaller, length of anterior wing 9 mm. ; bands of al)dominal segments 2 to 4 

 pale ochreous ■ . ■ -fratei* aragalli Ckll. 



Tetraloiiia eilwarilsii vngabuiida n. subsp. %. 



Hub. — Boulder, Colorado, June 4, 1905, at flowers of Onosmo- 

 dium, 5 S ( W. P. Cockerell). Hair of thorax above whitish ; 

 basal half of second abdominal segment with light hair; fifth seg- 

 ment with a light baud. Superficially much like T. fedoris, but 

 easily distinguished by the entii'ely different sculpture of mesothorax. 

 The characters of this form are best set forth by means of a table of 

 forms with a dull mesothorax : 



Smaller ; venter with a pair of conspicuous subapical keel-like teeth. 



territella Ckll. 

 Larger ; venter without such teeth 1. 



1. Apical segments of abdomen with much pale hair, sixtii with a lieavy dull 



white fringe; yellow of clypeus notched at sides; last ventral segment 

 with a large round basal pit at each extreme side, and a curved line 



or groove along lateral margins frater (Cress.). 



Apical segments of abdomen with much black hair, the pale hair when pres- 

 ent reduced to narrow bands 2. 



2. Face broader, yellow of clypeus not appioMcliing orbital margin (style of T. 



atriventris) ; second s. m. larger, receiving first r. n. some distance from 

 end ; apical segments of abdomen without noticeable light bands ; yel- 

 low of clypeus concave at sides, but not abruptly notched ; last ventral 

 segment rough basally, with short black bristles; laterally (but not 

 basally) the segment has a pit or depression, the inner edge of which 

 is somewhat raised, representing apparently a rudiment of such a 

 tooth as is found in territeUa ; submarginal area caudo-mesad of the 

 pit (nearly at right angles with it) broad and punctured, its end ill 



defined triilta^ Ckll. 



Face narrower, yellow of clypeus closely approaching orbital margin (style of 

 ucerha and edwardsii) ; second s. m. smaller, receiving the first r. n. 

 almost at its end ; yellow of clypeus abruptly (rectangularly) notched 

 at sides; last ventral segment similar to that of tridtx in most respects, 



TRANS. AM. ENT. SOC. XXXII. JANUARY, 1906. 



