Insects 153 



almost any cultivated plant. Thomas Say found this species 

 on Long's Expedition, and says of it: "This species, with several 

 others, occurred in great numbers near the mountains, and on 

 one occasion we observed this species in company with several 

 others, ascending to a great height in the air as if to commence 

 a migration to a remote region." In his description, he said the 

 posterior tibia were green, pale toward the tip and on the an- 

 terior side. They are very commonly darker than this would 

 imply, practically lead-color. In the Atlantic and Pacific States, 

 and across Canada, this insect is represented by a locust with 

 red hind tibiae, but otherwise not materially different. Speci- 

 mens of this red-legged species have been reported from Wyo- 

 ming and Colorado, but they are certainly extremely rare in 

 Colorado. The red-legged yellow-striped locust is called Melano- 

 plus femoratus, named by Burmeister in his Handbook of En- 

 tomology, 1838. Blatchley, in his account of the Orthoptera of 

 Indiana, states that M. bivittatus will mate with M. femoratus, 

 and he has found various specimens intermediate between the 

 two supposed species. He therefore considers femoratus a syn- 

 onym, but it agrees exactly with the definition of a subspecies, 

 and should accordingly be called M. bivittatus femoratus. 



Another large and destructive species, found especially at 

 lower altitudes, is the Melanoplus differ entialis of Uhler. The 

 females may be over 40 mm. long. This lacks the conspicuous 

 stripes of M. bivittatus, and the hind femora are variably marked 

 with black in the form of transverse bars. An exceedingly dark 

 (melanic) variation occurs (variety nigricans); as it is found in 

 the same localities as ordinary specimens, it is presumably a 

 mutation, showing Mendelian inheritance. 



The harlequin grasshopper, Dactylotum pictum of Cyrus 

 Thomas, is almost described by its popular name. It is only of 

 moderate size (females reach about 35 mm.) and has short wing- 

 pads, without functional organs of flight. The body is dark, 

 variegated with bright red in harlequin fashion. Two pale 

 stripes run down the middle of the face. Another interesting 

 genus, likely to be met with on the plains, is Hesperotettix, the 

 name meaning western grasshopper. The species are of medium 

 size, green, often with pretty markings. In the common H. 

 Viridis of Thomas, the thorax above has a median white stripe 



