THE 



Ohio Journal of Science 



PUBLISHED BY THE 



Ohio State Univkrsity Scientific Society 



Volume XVIII JUNE. 1918 No. 8 



TABLE OF CONTENTS 



Fenton— The Parasites of Leaf-Hoppers— Part III 285 



Barrows— A List of Ohio Spiders 297 



HiNE— Description of Seven Species of Asihis (Family Asilickt) ;->19 



Drake — North American Species of Teleonemia Occurring North of Mexico. 323 



THE PARASITES OF LEAF-HOPPERS. 



With Special Reference to Anteoninae. 



F. A. Fenton. 



PART III. 



The Effect of Parasitism on the Host. 



There has been comparatively little work done in regard to 

 the internal or cytological changes in the insect host brought 

 about by its parasite. Giard (1889) in working out the biology 

 of Aphelopus melaleucus parasitic on Erythroneura (Typhlocyba) 

 hippocastani, misinterpreted the real nature of the larval sac, 

 supposing that it was a true animal gall, "formed by a gradual 

 dilation of the hypodermis which secretes an abnormal cuticle 

 * * * " He proposed the name thylacies to those galls 

 produced in animals comparing the typhlocybid larval sac 

 with the tumors caused by Cuterebra on the skin of mammals. 

 He compared the genitalia of normal and parasitized E. hypo- 

 castani and E. doiiglasi. In the females of these two species the 

 ovipositor in parasitized individuals is greatly reduced and 

 functionless. In the males of E. douglasi very little change 

 is brought about in the penis which is comparatively simple, but 

 in E. hippocastani where this structure is a very complex eight- 

 branched organ it is reduced to six or even three branches, thus 

 greatly affecting the specific characters. Because of this 

 superficially it might be confused with E. rosce. Certain acces- 

 sory sex organs were also found to be affected by the dryinid. 



285 



