Vol.XLVIII. February, 1925. No. 2. 



BIOLOGICAL BULLETIN 



PHYSIOLOGY OF THE ORTHOPTERA. 



H VI !(. I, N Iu\ C< iNCENTRATION OF THE BLOOD AND Al.IM KNTARY 

 TRACT OF CERTAIN ORTHOPTERA (GRASSHOPPERS). 



JOSEPH HALL BODINE, 



1 LABORATORY, UNIVERSITY OF PENNSYLVANIA. 



investigations on the hydrogen ion concentration oi" 

 blood .tin I b<>dy fluids have dealt almost exclusively with higher 

 vertebrates and particularly with mammals. Little informal i. m 



ns to exist for lower forms, especially the insects. Cm/ier i 

 in recent work with transparent aquatic insect larva? has strik- 

 ingly >hn\vn the hydrogen ion concentration of different parts of 

 tin- aliment. in- canal, while Bishop (2) has pointed out the 

 hydrogen imi concentration of blood in the larva and pupa <>f the 

 hoiie\ bee. Jameson and Atkens (3) have studied the liydn . 

 ion Km. filtration of the blood and alimentary canal of the 

 silkunnn. Since no such information seems to exist for grass- 

 hnppers it was thought desirable to study the bio. "1 and ali- 

 nit IK.IIA < anal of these forms. The results herein presented are 

 ba-ed UJH.II large numbers of animals comprising seven t<-n 

 ilillcrcin -pci ir-. 



I'hr mrihi'd employed in determining the hydrogen ion 

 ( -i HH t -im.it i<m (pH) was a colorimetric one, essentially similar to 

 that (Ir-Miil.ed by Felton (4). Various dyes of the Clark and 

 I -ul) (5) series were used and in all cases dilUn-nt dyes were 

 emplnyed in checking results so that possible errors due to the 

 color of the blood or body fluids i -mild be eliminated. Blood was 

 collected from the body cavity under oil in capillary pipettes as 

 well as directly from an incision in the body \\all. No marked 

 dillcrcine- in pH values of blood collected with and \\ithout 

 exposure to ,iir \\ere noted when determinations were carried out 

 within one minute. The alimentary canal was usually taken out 



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