134 ROLAND THAXTER ON THE 



Xowakowslvi, and- 1 am also indebted to Pi'ofessor Farlow, Messrs. C. Y. Rile}', L. O. 

 Howai'd, Ileniy Edwards and A. F. Chatfield for several interesting specimens. To 

 Mr. C. W. Woodworth and Prof. S. W. Williston I also owe certain entomological de- 

 terminations. 



The plants that are to be considered in the jircsent paper belong to a class which, al- 

 though made up of sevei-al groups ditfering Avidely from one another in their habit and 

 affinities, is yet, by reason of a peculiarity common to all its members, possessed of a 

 certain individuality of its own that renders it susceptible of a consideration ajjart from 

 all other forms of plant life. Tliis peculiarity, by reason of which the class is usually 

 characterized as entomogenous or entomophytous, consists in an obligatory parasitism 

 \i})on insects, which, although in some instances it exists without apparent injur}* to the 

 insect host, is usually of such a nature as to cause its death; often resulting, especially 

 among noxious insects, in widespread mortalitj^ 



Although a few of the more common or conspicuous forms of entomophytous plants 

 had attracted the notice of botanists even in the last centui-y, it was not until within 

 comparatively recent years that they began to be studied with any care, and the work 

 of Kobin^ is the first contribution of importance on the sul)ject. This work still remains, 

 Avith two exceptions,^ the only attempt that has been made to bring together all the known 

 forms of insect parasites; biit since its publication ver^y important contributions have been 

 made to our knowledge of the subject, through the medium of numerous scattered 

 papers. 



My attention was first turned in this direction in the course of entomological studies 

 on the life-histories of certain insects; in the course of which I was often greatly annoyed 

 by losing large numbers of larvae and pupae through the agency of fungi. Having by 

 this means and from other sources accunuilated a certain amount of material, it was my 

 first intention to include in my paper all the entomogenons plants recorded from Amer- 

 ica; yet, owing to the many difficulties presented by the ascomycetous forms, involving 

 a careful study and comparison of more ainindant material than I could connnand, as 

 well as by reason of the considerable additions to our Entomophthoreae resulting from 

 my observations, I have decided to confine myself for the present to the members of this 

 fiunily, trusting to a future opportunity of extending my pajier in conformity with my 

 original plan. In the meantime a brief summary of the more important groups may not 

 be out of place in this connection, and will be a fitting introduction to the more detailed 

 consideration of the Entomophthoreae which follows. 



Summary of entomogenous j)lunts. — Although the spiders and myriapods are not ex- 

 empt from the attack of peculiar vegetable parasites, the hexapod insects ofter by far the 

 greater number of instances of this nature. Among the seven orders of the latter class 

 usually enumerated, the Xeuroptera and Orthoptera are almost wholly free from such 

 attack; and, luitil recently, the first named order was considered wholly exempt in this 

 respect. Of the remaining orders the Lepidoptera and Diptera are apparently the great- 

 est sufferers; while the Hemiptera, Coleoptera and Hymenoptera are about equally af- 



1 c. Robin, I. c. "I'll ^ii'c known to form the bases of fungokl parasites, 



'Sorokin, 1. c, C, and Gray, G. E : Notices of insects London, I8JS. 



