4 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 68^ 



Brachycistis. the other anatomical features being very much in favor 

 of this view. I present a sketch of the thoracic anatomy from the 

 side, showing the obhque ])leural suture similar to that of males of 

 Brachycistis (fig. 14), and the basal segment of the abdomen is 

 absolutely identical with that of the more robust males of that genus, 

 while absolutely different from that of males of Cyphotes with which 

 it lias been more closely linked in the past (figs. 15, 16). 



Males of Brachycistis are commonly attracted to lights wliere the 

 species occur and when running about give forth a squeaking sound 

 according to R. C. Shannon who collected specimens in Washington 

 State. It may be of interest to state that I had noted the ''stridula- 

 tory areas" on tlie fore coxae before I knew of the ability of tliese- 

 insects to produce sound, and that confirmation of ni}^ conjecture 

 that the insects stridulatc was obtained from Mr. Shannon before 

 he knew of my discovery. How these areas are used to produce 

 sound or even if my surmise that they are so used is correct I do not 

 know, but observation of living specimens will probably produce 

 evidence if these areas are utilized in this manner. 



Professor Cockerell in replying to a letter of mine in which I sug- 

 gested that mirdbilis might be the female of a species of Brachycistis 

 states that so far as he knows the former is diurnal and the Brachy- 

 cistis males are nocturnal. How^ever, he informs me that repeated 

 searches with a lantern after dark in localities where the males 

 abounded failed to disclose any females of the genus, apparentlj" 

 bearing out the supposition we both entertain that the temales remain 

 underground. 



In the summer of 1924 the Biological Survey had E. R. Hall in 

 the field at Pyramid Lake, Nev., and he picked up many specimens 

 of the genus Brachycistis which I have before me. A large number 

 of these specimens were taken by sweeping alfalfa between the hours 

 of 5 and 7 p. m. Others were taken at light. I give an extract from- 

 Mr. Hall's letter to me in reply to an inquiry of mine regarding the 

 habits of these species. 



The specimens of Hj^menoptera labeled as having been swept from alfalfa 

 were taken as early as 5 p. m. and as late as 7 p. m. While those taken at the 

 latter hour might be said to be crepuscular, none of the sweepings from alfalfa 

 were made after dark and the ones taken as early as 5 p. m. might indicate a 

 diurnal habit. Large numbers were also taken at night under my light as indi- 

 cated on the labels. I noticed that these insects produced a slight sound but 

 did not determine how this was accomplished. 



It is of interest to note that all the specimens of atrata Blake in. 

 this lot were swept from alfalfa, not one bearing a label to the effect 

 that this black species occurred at light. Most of the orange colored 

 specimens were taken at light, but a few have the same label as- 



