22 



PSYCHE. 



[February iSql. 



Geer. This species like the last is par- 

 tial to shrubs but it is much more com- 

 mon in the vicinity of houses in towns. 

 Its note is a quick shuffling sound which 

 resembles "Katy" or "Katy-did" very 

 slightly. It sometimes flies in the eve- 

 ning but much more rarely than S. cur- 

 vicattda. It makes its appearance in 

 the neighborhood of Moline about the 

 first of August. 



22. A. rotundifolia Scudder. This 

 species resembles the preceding in song 

 and habits. In northern Illinois it 

 makes its appearance about the tenth of 

 August. 



23 . Microcentrum laurifolium Linn . 

 I have never captured this species at 

 Moline nor have I heard its note there? 

 which may be represented by the sylla- 

 ble "tic" repeated from eight to twenty 

 times at the rate of about four to the sec- 

 ond. It is a tree-loving species, very 

 common in Missouri, according to Ri- 

 ley, and therefore presumably common 

 in southern Illinois. 



24. Cyrtopkylhts concavus Harr. 

 This is the true "Katydid," common 

 wherever there are trees. Its song is 

 better known and the insect itself less 

 known, because of its arboreal habits, 

 than either of the other katydids. This 

 sjDecies moves about so little that it is 

 not unlikely that in many cases an indi- 

 vidual spends its whole life upon a single 

 tree. I have listened to the song of one 

 katydid on a certain tree every even- 

 ing for more than two months. I have 

 noticed repeatedly that on any evening 

 when they are singing there are the 

 same number of individuals, as indicated 



by the number of songs. Of all the 

 specimens I have collected on the ground 

 or had presented to me, probably a 

 dozen, only a single one was a male. 

 I have collected in sweepings hundreds 

 of specimens of the young of Scudderia 

 and Amblycorypha but not one of Mi- 

 crocentrum or Cyrtophyllus ; but if Mi- 

 crocentrum does not leave the trees when 

 in the larval and pupal stages it certainly 

 does when it reaches maturity. It is 

 then a great wanderer, coming frequently 

 to the electric light. I have never 

 known Cyrtophyllus to come to a light. 

 So far as I know this is the only species 

 of Orthoptera in which the male is not 

 smaller and more active than the female. 

 It is the only green, winged Locustid 

 with which I am acquainted that does 

 not have the wings longer than the ely- 

 tra. These facts are not improbably 

 mutually related. It may be surmised 

 that, in the evolution of species, the katy- 

 did that developed in the greatest degree 

 its musical apparatus had the least need 

 of hunting up his partner when the mat- 

 ing season came round, and as it was 

 so well protected by its form and color 

 and arboreal habits as to have little need 

 of wings, these organs have gradually 

 degenerated into a musical and protec- 

 tive apparatus. As the male was re- 

 leased from the necessity of hunting up 

 the female, he would naturally lose after 

 a time his slighter but more active body : 

 it is easy to see how arboreal habits 

 once acquired may react upon the entire 

 organization. If at first glance it seems 

 strange that two species so much alike 

 as Oecanthns niveiis and OecautJius 



