11 



the error was excusable, because Dr. Riley really bad under obser- 

 vation a closely allied species which could not, at that time, and from 

 the literature at hand, be easily distinguished from the more com- 

 mon Geresa huhalus. Dr. liiley has shown in a recent communication 

 before the Entomological Society of Washington that his description, 

 and tigures of the eggs, relate to Geresa taurina Fitch, a somewhat 

 smaller and comparatively rare species. The general appearance of 

 this latter insect is shown for purposes of comparison in the accom- 

 panying illustration (Fig. 5, a, b), and the peculiar row of little raised 

 egg-slits in the bark, each of which contains a single oval egg, are 

 shown at Fig. 6, a, h. 



HABIT8 AND LIFE-HISTORY, 



The habits and life-history of the true buffalo tree-hopper are as fol- 

 loAvs: The adult insect chooses as a nidus for its eggs the twigs, pref 

 erablj^ those of two or three years' growth, of various trees, particularly 

 the apple, willow, cottonwood, maple, etc.; 

 confines itself in general to the upper sur- 

 face of the twigs, and works more abund- 

 antly on the south side of the tree than on 

 the north, although in this lespect the pre- 

 vailing winds and other conditions influ- 

 ence the insect. The eggs are deposited 

 quite as readily in the new growth of old 

 trees as in young trees, but the damage is 

 much more noticeable in the latter case. 

 The eggs are placed in small compound 

 groups arranged in two nearly parallel or 

 slightly curved slits extending in the direc- 

 tion of the twig about three-sixteenths of 

 an inch in length, and separated by one- 

 eighth inch or less of bark (Fig. 7, h). 

 Facing either toward or away from the 

 trunk, the female makes with its ovipositor 

 a slightly curved slit through the outer bark, cutting in a direction pos- 

 terior to the insect, so that the ovipositor, which is at first extended 

 nearly at right angles to the body, at the completion of the slit, lies 

 almost against the abdomen. The eggs are inserted very obliquely 

 through the bai k and nearly at right angles to the twig, immediately 

 after the completion of the pr. liminary incision, beginning at the end of 

 the slit last made, and are thrust well down into the cambium layer 

 between the bark and the wood (Fig. 7, c). A i^eriod of from one-half to 

 two minutes is required for the insertion of each egg, after which the 

 ovipositor is partly withdrawn, moved a little forward, and re-inserted, 

 about twenty minutes being required for the catting of the slit and filling 

 it with eggs,which, in each slit, vary in numbers from to 12. As soon as 

 the first slit is completed a second one is made parallel to and slightly 



Fig. 6. — Geresa taurina Fitch- a, 

 twig showing rows of egg slits, 

 natural size ; h, one egg slit enlarged, 

 showing egg; c, larva; d, nymph— 

 last two enlarged (copied from 

 Rilev). 



