OF WASHINGTON, VOLUME XV, 1913. 99 



The host was determined by Mr. E. W. Nelson, of the Biological 

 Survey, Washington. 



Regarding the venation of the Streblidce, it must be noted that 

 the veins appear to have evoluted outwardly or distally, especially 

 the inner basal veins, greatly elongating the second and third basal 

 cells from the Holometopan type by drawing their crossveins 

 nearer to the wing-tip. Hence what is called in the above descrip- 

 tion the extra hind crossvein is probably the crossvein of the anal 

 or third basal cell, and the first or outer hind crossvein (between 

 the fourth and fifth veins) is probably the cross vein of the second 

 basal cell, while the true (Holometopan) hind cross vein has been 

 lost. At all events these second and third basal-cell crossveins are 

 no longer apparent in their ordinary position (judged by the Holo- 

 metopan type) in the Streblidce, and the general outward trend of 

 all the veins exhibited by this family supports the above conclu- 

 sion. The effect has perhaps been accelerated by a concurrent 

 shortening of the wings, as suggested in Aspidoptera. 



Synthesiostrebla stands farther removed from Strebla on both 

 venational and mesoscutal characters than does Trichobius. It 

 represents a relatively less outward evolution of the veins than that 

 shown in any hitherto known Streblid genera, and thus appears to 

 be a persisting fragment of an older and probably an ancient Pupi- 

 parous stock. The fourth, fifth and sixth veins do not reach the 

 wing border, stopping farther from latter than in Trichobius, while 

 even the third vein stops slightly short of apical border. The 

 form is in all probability a relic by direct descent from an old stock 

 stranded in western America since the Mesozoic -a stock that 

 accompanied the northward dispersals between Antarctic and 

 South America during or prior to the Cretaceous. 



Actual date of publication, June, 10, 1913. 



