100 BULLETIN 190, UNITED STATES NATIONAL MUSEUM 



enormous, tough-fibered roots penetrating the ground equally deep. The 

 larval galleries in the roots go down several feet. Excavating them is most 

 difficult. A fortunate opportunity to study the habits of the borer was 

 afforded on a visit to southern Arizona in the spring of 1935. One of the 

 so-called "dry washes," caused by a cloudburst, had recently cut ofi ver- 

 tically large parts of an embankment, exposing plants of Hymenodea in 

 their entirety. Many of the roots showed the extensive tunnels of the 

 larvae and their places of pupation nearer to the crown of the root. The 

 moths emerged during August and September. Whether this insect is an 

 annual or a biannual species could not be determined. There are long 

 periods of estivation. Of the three known female types from the original 

 lot collected by Kuntze at Phoenix, Ariz., one is in the collection of the 

 United States National Museum, bearing Beutenmiiller's label and designa- 

 tion as "type." It has been made the lectotype. Additional records in the 

 United States National Museum: 26 males, 7 females, Mohave County, 

 Ariz., September 1, 1930; 5 males, 3 females, Kingman, Mohave County, 

 Ariz., October 1-7; 3 males, 6 females, Marfa, Presidio County, Tex., 

 October 1926 (O. C. Poling) ; 1 male, 2 females, Alpine, Brewster County, 

 Tex., 5,000 feet, September 5, 1926 (Engelhardt). 



Genus ALCATHOE Hy. Edwards 



Alcathoe Hy. Edwards, Papilio, vol. 2, p. 53, 1882. (Genotype, Aegeria caiidata 

 Harris.) 



Tongue long, spiraled. Male antenna long, only slightly dilated before 

 tip, finely and shortly bipectinate; female antennae simple. Labial palpi 

 ascending, projecting beyond the head; second joint slightly thickened 

 with nearly smooth scales, third joint about half the length of second, 

 bluntly pointed. Posterior tibia rough-scaled to the middle spurs, smooth 

 to the last spur, where it is again tufted ; first tarsal joint heavily tufted 

 above. Eighth abdominal segment of the male with two short lateral tufts 

 and one central very long, soft, hairy appendage as long as, or longer tha.n, 

 the abdomen. Forewing with 11 veins, veins 10 and 11 coalescent; hind- 

 wing with veins 3 and 4 on short stalk. Male genitalia of the Synanthedon 

 type, sacculus ridge curved, densely covered with furcate scales a.nd 

 terminating in a recurved, convoluted, unsealed fold; aedeagus slightly 

 bent, with a somewhat bulbous base; cornuti prominent, stout, paired 

 spines; vinculum stout, blunt, moderately long. Female genitalia with 

 ductus rather short, strongly sclerotized on outer half ; bursa oval, finely 

 granulated, without signum. 



The species of this genus form a singular unit, distinguished by the long, 

 delicate caudal appendage of the male and by the remarkable resemblance 

 of both sexes to members of the Psammocharidae, and in particular to 

 species of Pepsis, the so-called tarantula-killer wasps. The resemblance 

 between western species of the moths and wasps during flight is so decep- 



