December, '15] PARROTT, GLOYER AND FULTON: TREE-CRICKETS 



539 



The process of egg deposition is briefly as follows: The female, 

 having selected a suitable spot on the tree, first gnaws a hole in the 

 bark. She then advances forward, and moving the ovipositor at right 

 angles to her body, inserts the tip of it in the wound and proceeds to 

 bore the hole for the reception of the egg. The drilling is accom- 

 plished by a thrusting and rotating motion of the ovipositor. After 

 boring to a suitable depth, the egg is deposited. An adhesive substance 

 is then discharged, which is kneaded about the egg by the ovipositor. 

 Attention is also called to the curious habit of the female which, at 

 the conclusion of the drilling operation, usually defecates and then, 

 when the egg is deposited, conveys the excreta by means of her mouth 

 to the wound and gently kneads it to form a neat cap to the opening. 



In studying the feeding and oviposition habits of the snowy tree- . 

 cricket it appears that infection of apple bark might take place as a 

 result of (1) wounds produced by the gnawing of the bark by the 

 female as the initial step in the act of oviposition; (2) by means of 

 the ovipositor, the adhesive substance discharged at the time of dep- 

 osition, serving to collect and to hold the spores which may later be 

 left in the holes during the drilling process; and (3) by the introduction 

 of spores in the oviposition wounds on account of the remarkable habits 

 of the insect, which employs its excreta to close the openings in the 

 bark after the deposition of the egg. Our attention has largely been 

 devoted to the consideration of the last point, which has involved a 

 study of the viability of the mycelia and spores of fungi after passage 

 through the intestinal tract of a number of the crickets and experi- 

 ments in the orchard using tree crickets as carriers of the spores of 

 several of the more important bark diseases of the apple. 



In our work to determine the effects of the digestive processes of 

 the insects upon the vitality of the spores the following methods 

 were employed: Tree crickets to the number of twelve to twenty 

 individuals were confined in breeding cages containing raspberry 

 shoots and apple twigs which were abundantly infested with plant 

 lice. Spores of various fungi were introduced into the breeding cages 

 in a 5 per cent cane-sugar solution which was atomized over the 

 foliage or through sections of wood which were affected by some of 

 the common bark diseases. At varying intervals of time microscopi- 

 cal and cultural studies were made of the excreta to classify the differ- 

 ent species of spores in the alimentary wastes and to determine their 

 viability in ordinary agar cultures. 



Some of the more interesting results obtained in these tests may be 

 briefly summarized as follows: 



1. The crickets fed readily on diseased areas of apple and 

 raspberry canes, even when foliage and lice were abundantly 



