GRASSHOPPERS — GURNEY AND BROOKS 29 



times "light swarms of what appeared to be nearly typical spretus 

 entered Iowa from the northwest and settled down in the western 

 and southwestern parts of the state" (Drake and Tauber, 1946). 

 The aedeagus of this specimen appears to be abnormal, but an 

 explanation of this condition merits future attention. 



Special interest is attached to the material reared by Brett (1947) 

 which he ascribed to M. mexicanus and the most long-winged speci- 

 mens of which he believed comparable to spretus, the latter considered 

 by him a synonym. Specimens were deposited in the U. S. National 

 Museum by Dr. Brett, and additional ones have been loaned by 

 F. A. Fenton of Oklahoma A. & M. College, where Brett's main 

 reared series are preserved. He reared specimens in cages, mainly 

 feeding head lettuce, alfalfa, corn, and sorghum. The largest indi- 

 viduals reared were fed head lettuce at 100° F. and 35 percent and 

 50 percent relative humidity. Some of them resembled spretus in 

 body size and tegminal length, though none of them examined by us 

 has the spretus-tjpe of aedeagus. At the other extreme, individuals 

 reared on alfalfa were comparatively small, and in many of those 

 reared under cool, humid conditions the tegmina were poorly developed 

 as well as short. 



The aedeagus of a total of 65 males from the Brett material has 

 been examined, these specimens representing the extremes of temper- 

 ature and relative humidity under which rearing occurred, as well 

 as tegminal lengths varying from abortive to extending as much as 

 6 mm. posterior to the hind femoral apices. Dr. Brett has informed 

 us (in litt., Dec. 17, 1956) that his stcck used at temperatures of 75° 

 and 80° F. was collected at Bennet, Nebr. (about 11 miles southeast 

 of Lincoln), that stock for rearings at temperatures above 80° was 

 collected near Stillwater, Okla., and that no Kansas stock was used. 

 Reared material from both the Nebraska and Oklahoma stocks is 

 variable in the structure of the dorsal value of the aedeagus, and there 

 are indications that both stocks are from tension areas where bilituratus 

 bilituratus and bilituratus vulturnus influence occurs, but the great 

 majority of males may readily be recognized as bilituratus vulturnus 

 and we have not considered them intergrades. Males collected at 

 Lincoln, Nebr., and Stillwater, Okla., are comparable to the reared 

 series in aedeagal structures and variation. No reared specimen 

 has an aedeagus like that of spretus, but several reared specimens 

 have the dorsal valve well sclerotized and with little of the shape 

 characteristic of adults of bilituratus vulturnus. It seems most likely 

 that the aedeagus of these specimens failed to mature completely, 

 though the cerci, supra-anal plate, and subgenital plate are, with 

 few exceptions, the type normal for adult bilituratus vulturnus. The 

 tegmina of these particular specimens are mostly abortive or mal- 



