60 DISEASES OF FIELD & GARDEN CROPS. [OH. 



fungus whilst they are still alive. The illustration at Fig. 

 21 shows a wasp, twice the natural size, as caught in a 

 living state in this country, languidly flying about with a 

 fungus burden, which may either be a Stilbum, as figured 

 by Charles Eobin in his Histoire Naturelle des Vty&aux 

 Parasites (Paris, 1853), or an abnormal form of the 

 Isaria condition of the fungus known as Torrubia spheco- 

 cephala, Kl. 



The genus Isaria amongst fungi represents an early or 

 larval state of another and more perfect genus of fungi 

 named Cordiceps, from the Greek Jcordyle, in allusion to its 

 clublike shape, a genus termed in more modern books 

 TorruUa. 



Now the species belonging to Cordiceps or Torrubia 

 (certainly in many instances the perfect state of Isaria) 

 are equally curious in their habits with Isaria itself; 

 some grow on larvae and pupse, even when buried in the 

 ground ; two grow on subterranean truffles, and it is 

 remarkable that two distinct species of Torrubia attack 

 two equally distinct truffles ; another species grows on 

 Wych elm twigs. It is well to mention at this place 

 that Torrubia is very closely allied to the fungus named 

 Claviceps, which is the perfect condition of the dangerous 

 ergot of rye. 



As it is quite possible that Isaria fuciformis, B., may 

 be an early condition of a Torrubia belonging to an insect 

 or plant host, a brief description of one of the species of 

 Torrubia may be useful. The genus Torrubia is named 

 in honour of a Spanish botanist who wrote a work on 

 " vegetable wasps." A Torrubia parasitic on the truffle 

 named Elaphomyces muricatus, Vitt., is fairly com- 

 mon. This curious parasite is named Torrubia ophio- 

 glossoides, Tul., the specific name having reference to a 

 fanciful resemblance between the head of the perfect 

 fungus and a serpent's tongue. This Torrubia is repre- 

 sented, natural size, at A, Fig. 22, attached to its peculiar 

 host or truffle, B. The club-shaped top of the Torrubia 



